update: add outline color as constant

This shows the time in different timezones

base/src/constants.rs

@@ -12,6 +12,9 @@ pub(crate) const DEFAULT_WINDOW_WIDTH: i64 = 800;
 pub(crate) const LAST_COLUMN: i32 = 16_384;
 pub(crate) const LAST_ROW: i32 = 1_048_576;
 
+// Excel uses 15 significant digits of precision for all numeric calculations.
+pub(crate) const EXCEL_PRECISION: usize = 15;
+
 // 693_594 is computed as:
 // NaiveDate::from_ymd(1900, 1, 1).num_days_from_ce() - 2
 // The 2 days offset is because of Excel 1900 bug

base/src/expressions/parser/mod.rs

@@ -471,6 +471,20 @@ impl Parser {
             Node::NumberKind(s) => ArrayNode::Number(s),
             Node::StringKind(s) => ArrayNode::String(s),
             Node::ErrorKind(kind) => ArrayNode::Error(kind),
+            Node::UnaryKind {
+                kind: OpUnary::Minus,
+                right,
+            } => {
+                if let Node::NumberKind(n) = *right {
+                    ArrayNode::Number(-n)
+                } else {
+                    return Err(Node::ParseErrorKind {
+                        formula: self.lexer.get_formula(),
+                        message: "Invalid value in array".to_string(),
+                        position: self.lexer.get_position() as usize,
+                    });
+                }
+            }
             error @ Node::ParseErrorKind { .. } => return Err(error),
             _ => {
                 return Err(Node::ParseErrorKind {
@@ -490,6 +504,20 @@ impl Parser {
                 Node::NumberKind(s) => ArrayNode::Number(s),
                 Node::StringKind(s) => ArrayNode::String(s),
                 Node::ErrorKind(kind) => ArrayNode::Error(kind),
+                Node::UnaryKind {
+                    kind: OpUnary::Minus,
+                    right,
+                } => {
+                    if let Node::NumberKind(n) = *right {
+                        ArrayNode::Number(-n)
+                    } else {
+                        return Err(Node::ParseErrorKind {
+                            formula: self.lexer.get_formula(),
+                            message: "Invalid value in array".to_string(),
+                            position: self.lexer.get_position() as usize,
+                        });
+                    }
+                }
                 error @ Node::ParseErrorKind { .. } => return Err(error),
                 _ => {
                     return Err(Node::ParseErrorKind {

base/src/expressions/parser/static_analysis.rs

@@ -872,12 +872,10 @@ fn get_function_args_signature(kind: &Function, arg_count: usize) -> Vec<Signatu
         Function::Combin => args_signature_scalars(arg_count, 2, 0),
         Function::Combina => args_signature_scalars(arg_count, 2, 0),
         Function::Sumsq => vec![Signature::Vector; arg_count],
-
         Function::N => args_signature_scalars(arg_count, 1, 0),
         Function::Sheets => args_signature_scalars(arg_count, 0, 1),
         Function::Cell => args_signature_scalars(arg_count, 1, 1),
         Function::Info => args_signature_scalars(arg_count, 1, 1),
-
         Function::Daverage => vec![Signature::Vector, Signature::Scalar, Signature::Vector],
         Function::Dcount => vec![Signature::Vector, Signature::Scalar, Signature::Vector],
         Function::Dget => vec![Signature::Vector, Signature::Scalar, Signature::Vector],
@@ -890,7 +888,6 @@ fn get_function_args_signature(kind: &Function, arg_count: usize) -> Vec<Signatu
         Function::Dvar => vec![Signature::Vector, Signature::Scalar, Signature::Vector],
         Function::Dvarp => vec![Signature::Vector, Signature::Scalar, Signature::Vector],
         Function::Dstdevp => vec![Signature::Vector, Signature::Scalar, Signature::Vector],
-
         Function::BetaDist => args_signature_scalars(arg_count, 4, 2),
         Function::BetaInv => args_signature_scalars(arg_count, 3, 2),
         Function::BinomDist => args_signature_scalars(arg_count, 4, 0),
@@ -929,6 +926,7 @@ fn get_function_args_signature(kind: &Function, arg_count: usize) -> Vec<Signatu
         Function::FDistRT => args_signature_scalars(arg_count, 3, 0),
         Function::FInv => args_signature_scalars(arg_count, 3, 0),
         Function::FInvRT => args_signature_scalars(arg_count, 3, 0),
+        Function::FTest => vec![Signature::Vector; 2],
         Function::Fisher => args_signature_scalars(arg_count, 1, 0),
         Function::FisherInv => args_signature_scalars(arg_count, 1, 0),
         Function::Gamma => args_signature_scalars(arg_count, 1, 0),
@@ -989,6 +987,26 @@ fn get_function_args_signature(kind: &Function, arg_count: usize) -> Vec<Signatu
                 vec![Signature::Error; arg_count]
             }
         }
+        Function::Sumx2my2 => vec![Signature::Vector; 2],
+        Function::Sumx2py2 => vec![Signature::Vector; 2],
+        Function::Sumxmy2 => vec![Signature::Vector; 2],
+        Function::Correl => vec![Signature::Vector; 2],
+        Function::Rsq => vec![Signature::Vector; 2],
+        Function::Intercept => vec![Signature::Vector; 2],
+        Function::Slope => vec![Signature::Vector; 2],
+        Function::Steyx => vec![Signature::Vector; 2],
+        Function::Gauss => args_signature_scalars(arg_count, 1, 0),
+        Function::Harmean => vec![Signature::Vector; arg_count],
+        Function::Kurt => vec![Signature::Vector; arg_count],
+        Function::Large => vec![Signature::Vector, Signature::Scalar],
+        Function::MaxA => vec![Signature::Vector; arg_count],
+        Function::Median => vec![Signature::Vector; arg_count],
+        Function::MinA => vec![Signature::Vector; arg_count],
+        Function::RankAvg => vec![Signature::Scalar, Signature::Vector, Signature::Scalar],
+        Function::RankEq => vec![Signature::Scalar, Signature::Vector, Signature::Scalar],
+        Function::Skew => vec![Signature::Vector; arg_count],
+        Function::SkewP => vec![Signature::Vector; arg_count],
+        Function::Small => vec![Signature::Vector, Signature::Scalar],
     }
 }
 
@@ -1014,7 +1032,7 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::Atan => scalar_arguments(args),
         Function::Atan2 => scalar_arguments(args),
         Function::Atanh => scalar_arguments(args),
-        Function::Choose => scalar_arguments(args), // static_analysis_choose(args, cell),
+        Function::Choose => scalar_arguments(args),
         Function::Column => not_implemented(args),
         Function::Columns => not_implemented(args),
         Function::Cos => scalar_arguments(args),
@@ -1061,7 +1079,6 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::Lookup => not_implemented(args),
         Function::Match => not_implemented(args),
         Function::Offset => static_analysis_offset(args),
-        // FIXME: Row could return an array
         Function::Row => StaticResult::Scalar,
         Function::Rows => not_implemented(args),
         Function::Vlookup => not_implemented(args),
@@ -1253,7 +1270,6 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::Sheets => scalar_arguments(args),
         Function::Cell => scalar_arguments(args),
         Function::Info => scalar_arguments(args),
-
         Function::Dget => not_implemented(args),
         Function::Dmax => not_implemented(args),
         Function::Dmin => not_implemented(args),
@@ -1266,7 +1282,6 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::Dvar => not_implemented(args),
         Function::Dvarp => not_implemented(args),
         Function::Dstdevp => not_implemented(args),
-
         Function::BetaDist => StaticResult::Scalar,
         Function::BetaInv => StaticResult::Scalar,
         Function::BinomDist => StaticResult::Scalar,
@@ -1287,6 +1302,7 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::FDistRT => StaticResult::Scalar,
         Function::FInv => StaticResult::Scalar,
         Function::FInvRT => StaticResult::Scalar,
+        Function::FTest => StaticResult::Scalar,
         Function::Fisher => StaticResult::Scalar,
         Function::FisherInv => StaticResult::Scalar,
         Function::Gamma => StaticResult::Scalar,
@@ -1322,5 +1338,25 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::VarA => StaticResult::Scalar,
         Function::WeibullDist => StaticResult::Scalar,
         Function::ZTest => StaticResult::Scalar,
+        Function::Sumx2my2 => StaticResult::Scalar,
+        Function::Sumx2py2 => StaticResult::Scalar,
+        Function::Sumxmy2 => StaticResult::Scalar,
+        Function::Correl => StaticResult::Scalar,
+        Function::Rsq => StaticResult::Scalar,
+        Function::Intercept => StaticResult::Scalar,
+        Function::Slope => StaticResult::Scalar,
+        Function::Steyx => StaticResult::Scalar,
+        Function::Gauss => StaticResult::Scalar,
+        Function::Harmean => StaticResult::Scalar,
+        Function::Kurt => StaticResult::Scalar,
+        Function::Large => StaticResult::Scalar,
+        Function::MaxA => StaticResult::Scalar,
+        Function::Median => StaticResult::Scalar,
+        Function::MinA => StaticResult::Scalar,
+        Function::RankAvg => StaticResult::Scalar,
+        Function::RankEq => StaticResult::Scalar,
+        Function::Skew => StaticResult::Scalar,
+        Function::SkewP => StaticResult::Scalar,
+        Function::Small => StaticResult::Scalar,
     }
 }

base/src/functions/date_and_time.rs

@@ -4,6 +4,7 @@ use chrono::Months;
 use chrono::NaiveDateTime;
 use chrono::NaiveTime;
 use chrono::Timelike;
+use chrono_tz::Tz;
 
 const SECONDS_PER_DAY: i32 = 86_400;
 const SECONDS_PER_DAY_F64: f64 = SECONDS_PER_DAY as f64;
@@ -770,12 +771,12 @@ impl Model {
         Ok(values)
     }
 
-    // Returns the current date/time as an Excel serial number in the model's configured timezone.
+    // Returns the current date/time as an Excel serial number in the given timezone.
     // Used by TODAY() and NOW().
-    fn current_excel_serial(&self) -> Option<f64> {
+    pub(crate) fn current_excel_serial_with_timezone(&self, tz: Tz) -> Option<f64> {
         let seconds = get_milliseconds_since_epoch() / 1000;
         DateTime::from_timestamp(seconds, 0).map(|dt| {
-            let local_time = dt.with_timezone(&self.tz);
+            let local_time = dt.with_timezone(&tz);
             let days_from_1900 = local_time.num_days_from_ce() - EXCEL_DATE_BASE;
             let fraction = (local_time.num_seconds_from_midnight() as f64) / (60.0 * 60.0 * 24.0);
             days_from_1900 as f64 + fraction
@@ -978,7 +979,7 @@ impl Model {
                 message: "Wrong number of arguments".to_string(),
             };
         }
-        match self.current_excel_serial() {
+        match self.current_excel_serial_with_timezone(self.tz) {
             Some(serial) => CalcResult::Number(serial.floor()),
             None => CalcResult::Error {
                 error: Error::ERROR,
@@ -989,14 +990,35 @@ impl Model {
     }
 
     pub(crate) fn fn_now(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
-        if !args.is_empty() {
+        if args.len() > 1 {
             return CalcResult::Error {
                 error: Error::ERROR,
                 origin: cell,
                 message: "Wrong number of arguments".to_string(),
             };
         }
-        match self.current_excel_serial() {
+        let tz = match args.first() {
+            Some(arg0) => {
+                // Parse timezone argument
+                let tz_str = match self.get_string(arg0, cell) {
+                    Ok(s) => s,
+                    Err(e) => return e,
+                };
+                let tz: Tz = match tz_str.parse() {
+                    Ok(tz) => tz,
+                    Err(_) => {
+                        return CalcResult::Error {
+                            error: Error::VALUE,
+                            origin: cell,
+                            message: format!("Invalid timezone: {}", &tz_str),
+                        }
+                    }
+                };
+                tz
+            }
+            None => self.tz,
+        };
+        match self.current_excel_serial_with_timezone(tz) {
             Some(serial) => CalcResult::Number(serial),
             None => CalcResult::Error {
                 error: Error::ERROR,

base/src/functions/mathematical.rs

@@ -1,81 +1,15 @@
 use crate::cast::NumberOrArray;
-use crate::constants::{LAST_COLUMN, LAST_ROW};
+use crate::constants::{EXCEL_PRECISION, LAST_COLUMN, LAST_ROW};
 use crate::expressions::parser::ArrayNode;
 use crate::expressions::types::CellReferenceIndex;
 use crate::functions::math_util::{from_roman, to_roman_with_form};
-use crate::number_format::to_precision;
+use crate::number_format::{to_excel_precision, to_precision};
 use crate::single_number_fn;
 use crate::{
     calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
 };
-use statrs::function::gamma::ln_gamma;
-use std::f64::consts::LN_2;
 use std::f64::consts::PI;
 
-const FACT_TABLE: [f64; 26] = [
-    1.0,                          // 0!
-    1.0,                          // 1!
-    2.0,                          // 2!
-    6.0,                          // 3!
-    24.0,                         // 4!
-    120.0,                        // 5!
-    720.0,                        // 6!
-    5040.0,                       // 7!
-    40320.0,                      // 8!
-    362880.0,                     // 9!
-    3628800.0,                    // 10!
-    39916800.0,                   // 11!
-    479001600.0,                  // 12!
-    6227020800.0,                 // 13!
-    87178291200.0,                // 14!
-    1307674368000.0,              // 15!
-    20922789888000.0,             // 16!
-    355687428096000.0,            // 17!
-    6402373705728000.0,           // 18!
-    121645100408832000.0,         // 19!
-    2432902008176640000.0,        // 20!
-    51090942171709440000.0,       // 21!
-    1124000727777607680000.0,     // 22!
-    25852016738884976640000.0,    // 23!
-    620448401733239439360000.0,   // 24!
-    15511210043330985984000000.0, // 25!
-];
-
-const FACTDOUBLE_TABLE: [f64; 32] = [
-    1.0,
-    1.0,
-    2.0,
-    3.0,
-    8.0,
-    15.0,
-    48.0,
-    105.0,
-    384.0,
-    945.0,
-    3840.0,
-    10395.0,
-    46080.0,
-    135135.0,
-    645120.0,
-    2027025.0,
-    10321920.0,
-    34459425.0,
-    185794560.0,
-    654729075.0,
-    3715891200.0,
-    13749310575.0,
-    81749606400.0,
-    316234143225.0,
-    1961990553600.0,
-    7905853580625.0,
-    51011754393600.0,
-    213458046676875.0,
-    1428329123020800.0,
-    6190283353629370.0,
-    42849873690624000.0,
-    191898783962511000.0,
-];
-
 #[cfg(not(target_arch = "wasm32"))]
 pub fn random() -> f64 {
     rand::random()
@@ -1050,7 +984,9 @@ impl Model {
             };
         }
 
-        let result = f64::floor(value / significance) * significance;
+        // Apply Excel precision to the ratio to handle floating-point rounding errors
+        let ratio = to_excel_precision(value / significance, EXCEL_PRECISION);
+        let result = f64::floor(ratio) * significance;
         CalcResult::Number(result)
     }
 
@@ -1187,10 +1123,14 @@ impl Model {
         }
         let significance = significance.abs();
         if value < 0.0 && mode != 0.0 {
-            let result = f64::ceil(value / significance) * significance;
+            // Apply Excel precision to handle floating-point rounding errors
+            let ratio = to_excel_precision(value / significance, EXCEL_PRECISION);
+            let result = f64::ceil(ratio) * significance;
             CalcResult::Number(result)
         } else {
-            let result = f64::floor(value / significance) * significance;
+            // Apply Excel precision to handle floating-point rounding errors
+            let ratio = to_excel_precision(value / significance, EXCEL_PRECISION);
+            let result = f64::floor(ratio) * significance;
             CalcResult::Number(result)
         }
     }
@@ -1220,7 +1160,9 @@ impl Model {
             return CalcResult::Number(0.0);
         }
 
-        let result = f64::floor(value / significance) * significance;
+        // Apply Excel precision to handle floating-point rounding errors
+        let ratio = to_excel_precision(value / significance, EXCEL_PRECISION);
+        let result = f64::floor(ratio) * significance;
         CalcResult::Number(result)
     }
 
@@ -1385,78 +1327,35 @@ impl Model {
     single_number_fn!(fn_sec, |f| Ok(1.0 / f64::cos(f)));
     single_number_fn!(fn_sech, |f| Ok(1.0 / f64::cosh(f)));
     single_number_fn!(fn_exp, |f: f64| Ok(f64::exp(f)));
-
     single_number_fn!(fn_fact, |x: f64| {
         let x = x.floor();
-
         if x < 0.0 {
             return Err(Error::NUM);
         }
-
-        if x == 0.0 {
-            return Ok(1.0);
+        let mut acc = 1.0;
+        let mut k = 2.0;
+        while k <= x {
+            acc *= k;
+            k += 1.0;
         }
-        if x < FACT_TABLE.len() as f64 {
-            return Ok(FACT_TABLE[x as usize]);
-        }
-
-        // Use ln Γ(x+1) to avoid overflow while deciding.
-        let ln_val = ln_gamma(x + 1.0);
-
-        // If gamma overflows or is invalid, map to NUM
-        if !ln_val.is_finite() || ln_val > f64::MAX.ln() {
-            return Err(Error::NUM);
-        }
-
-        Ok(ln_val.exp())
+        Ok(acc)
     });
-
     single_number_fn!(fn_factdouble, |x: f64| {
         let x = x.floor();
-        if x <= -1.0 {
+        if x < -1.0 {
             return Err(Error::NUM);
         }
-
-        if x <= 1.0 {
+        if x < 0.0 {
             return Ok(1.0);
         }
-
-        // From here x > 1 and integer
-        let n = x as i64;
-
-        if n < FACTDOUBLE_TABLE.len() as i64 {
-            return Ok(FACTDOUBLE_TABLE[n as usize]);
+        let mut acc = 1.0;
+        let mut k = if x % 2.0 == 0.0 { 2.0 } else { 1.0 };
+        while k <= x {
+            acc *= k;
+            k += 2.0;
         }
-
-        // n!! grows very fast, so we compute it using gamma in log-space:
-        //
-        // If n is even, n = 2k:
-        //   n!! = 2^k * k!
-        // If n is odd, n = 2k + 1:
-        //   n!! = (2k+1)! / (2^k * k!)
-        //
-        // and we use ln_gamma for factorials.
-
-        let ln_val = if n % 2 == 0 {
-            // even n = 2k
-            let k = (n / 2) as f64;
-            // ln(n!!) = k * ln(2) + ln(k!)
-            k * LN_2 + ln_gamma(k + 1.0)
-        } else {
-            // odd n = 2k + 1
-            let k = ((n - 1) / 2) as f64;
-            let nn = n as f64;
-            // ln(n!!) = ln((2k+1)!) - (k * ln(2) + ln(k!))
-            ln_gamma(nn + 1.0) - (k * LN_2 + ln_gamma(k + 1.0))
-        };
-
-        if !ln_val.is_finite() || ln_val > f64::MAX.ln() {
-            return Err(Error::NUM);
-        }
-
-        Ok(ln_val.exp())
+        Ok(acc)
     });
-
     single_number_fn!(fn_sign, |f| {
         if f == 0.0 {
             Ok(0.0)

base/src/functions/mathematical_sum.rs

@@ -0,0 +1,230 @@
+use crate::expressions::types::CellReferenceIndex;
+
+use crate::{
+    calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
+};
+
+type TwoMatricesResult = (i32, i32, Vec<Option<f64>>, Vec<Option<f64>>);
+
+// Helper to check if two shapes are the same or compatible 1D shapes
+fn is_same_shape_or_1d(rows1: i32, cols1: i32, rows2: i32, cols2: i32) -> bool {
+    (rows1 == rows2 && cols1 == cols2)
+        || (rows1 == 1 && cols2 == 1 && cols1 == rows2)
+        || (rows2 == 1 && cols1 == 1 && cols2 == rows1)
+}
+
+impl Model {
+    // SUMX2MY2(array_x, array_y) - Returns the sum of the difference of squares
+    pub(crate) fn fn_sumx2my2(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let result = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(s) => return s,
+        };
+
+        let (_, _, values_left, values_right) = result;
+
+        let mut sum = 0.0;
+        for (x_opt, y_opt) in values_left.into_iter().zip(values_right.into_iter()) {
+            let x = x_opt.unwrap_or(0.0);
+            let y = y_opt.unwrap_or(0.0);
+            sum += x * x - y * y;
+        }
+
+        CalcResult::Number(sum)
+    }
+
+    // SUMX2PY2(array_x, array_y) - Returns the sum of the sum of squares
+    pub(crate) fn fn_sumx2py2(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let result = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(s) => return s,
+        };
+
+        let (_rows, _cols, values_left, values_right) = result;
+
+        let mut sum = 0.0;
+        for (x_opt, y_opt) in values_left.into_iter().zip(values_right.into_iter()) {
+            let x = x_opt.unwrap_or(0.0);
+            let y = y_opt.unwrap_or(0.0);
+            sum += x * x + y * y;
+        }
+
+        CalcResult::Number(sum)
+    }
+
+    // SUMXMY2(array_x, array_y) - Returns the sum of squares of differences
+    pub(crate) fn fn_sumxmy2(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let result = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(s) => return s,
+        };
+
+        let (_, _, values_left, values_right) = result;
+
+        let mut sum = 0.0;
+        for (x_opt, y_opt) in values_left.into_iter().zip(values_right.into_iter()) {
+            let x = x_opt.unwrap_or(0.0);
+            let y = y_opt.unwrap_or(0.0);
+            let diff = x - y;
+            sum += diff * diff;
+        }
+
+        CalcResult::Number(sum)
+    }
+
+    // Helper function to extract and validate two matrices (ranges or arrays) with compatible shapes.
+    // Returns (rows, cols, values_left, values_right) or an error.
+    pub(crate) fn fn_get_two_matrices(
+        &mut self,
+        args: &[Node],
+        cell: CellReferenceIndex,
+    ) -> Result<TwoMatricesResult, CalcResult> {
+        if args.len() != 2 {
+            return Err(CalcResult::new_args_number_error(cell));
+        }
+        let x_range = self.evaluate_node_in_context(&args[0], cell);
+        let y_range = self.evaluate_node_in_context(&args[1], cell);
+
+        let result = match (x_range, y_range) {
+            (
+                CalcResult::Range {
+                    left: l1,
+                    right: r1,
+                },
+                CalcResult::Range {
+                    left: l2,
+                    right: r2,
+                },
+            ) => {
+                if l1.sheet != l2.sheet {
+                    return Err(CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Ranges are in different sheets".to_string(),
+                    ));
+                }
+                let rows1 = r1.row - l1.row + 1;
+                let cols1 = r1.column - l1.column + 1;
+                let rows2 = r2.row - l2.row + 1;
+                let cols2 = r2.column - l2.column + 1;
+                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
+                    return Err(CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Ranges must be of the same shape".to_string(),
+                    ));
+                }
+                let values_left = self.values_from_range(l1, r1)?;
+                let values_right = self.values_from_range(l2, r2)?;
+                (rows1, cols1, values_left, values_right)
+            }
+            (
+                CalcResult::Array(left),
+                CalcResult::Range {
+                    left: l2,
+                    right: r2,
+                },
+            ) => {
+                let rows2 = r2.row - l2.row + 1;
+                let cols2 = r2.column - l2.column + 1;
+
+                let rows1 = left.len() as i32;
+                let cols1 = if rows1 > 0 { left[0].len() as i32 } else { 0 };
+                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
+                    return Err(CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Array and range must be of the same shape".to_string(),
+                    ));
+                }
+                let values_left = match self.values_from_array(left) {
+                    Err(error) => {
+                        return Err(CalcResult::new_error(
+                            Error::VALUE,
+                            cell,
+                            format!("Error in first array: {:?}", error),
+                        ));
+                    }
+                    Ok(v) => v,
+                };
+                let values_right = self.values_from_range(l2, r2)?;
+                (rows2, cols2, values_left, values_right)
+            }
+            (
+                CalcResult::Range {
+                    left: l1,
+                    right: r1,
+                },
+                CalcResult::Array(right),
+            ) => {
+                let rows1 = r1.row - l1.row + 1;
+                let cols1 = r1.column - l1.column + 1;
+
+                let rows2 = right.len() as i32;
+                let cols2 = if rows2 > 0 { right[0].len() as i32 } else { 0 };
+                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
+                    return Err(CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Range and array must be of the same shape".to_string(),
+                    ));
+                }
+                let values_left = self.values_from_range(l1, r1)?;
+                let values_right = match self.values_from_array(right) {
+                    Err(error) => {
+                        return Err(CalcResult::new_error(
+                            Error::VALUE,
+                            cell,
+                            format!("Error in second array: {:?}", error),
+                        ));
+                    }
+                    Ok(v) => v,
+                };
+                (rows1, cols1, values_left, values_right)
+            }
+            (CalcResult::Array(left), CalcResult::Array(right)) => {
+                let rows1 = left.len() as i32;
+                let rows2 = right.len() as i32;
+                let cols1 = if rows1 > 0 { left[0].len() as i32 } else { 0 };
+                let cols2 = if rows2 > 0 { right[0].len() as i32 } else { 0 };
+
+                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
+                    return Err(CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Arrays must be of the same shape".to_string(),
+                    ));
+                }
+                let values_left = match self.values_from_array(left) {
+                    Err(error) => {
+                        return Err(CalcResult::new_error(
+                            Error::VALUE,
+                            cell,
+                            format!("Error in first array: {:?}", error),
+                        ));
+                    }
+                    Ok(v) => v,
+                };
+                let values_right = match self.values_from_array(right) {
+                    Err(error) => {
+                        return Err(CalcResult::new_error(
+                            Error::VALUE,
+                            cell,
+                            format!("Error in second array: {:?}", error),
+                        ));
+                    }
+                    Ok(v) => v,
+                };
+                (rows1, cols1, values_left, values_right)
+            }
+            _ => {
+                return Err(CalcResult::new_error(
+                    Error::VALUE,
+                    cell,
+                    "Both arguments must be ranges or arrays".to_string(),
+                ));
+            }
+        };
+        Ok(result)
+    }
+}

base/src/functions/mod.rs

@@ -19,6 +19,7 @@ mod lookup_and_reference;
 mod macros;
 mod math_util;
 mod mathematical;
+mod mathematical_sum;
 mod statistical;
 mod subtotal;
 mod text;
@@ -76,6 +77,9 @@ pub enum Function {
     Sum,
     Sumif,
     Sumifs,
+    Sumx2my2,
+    Sumx2py2,
+    Sumxmy2,
     Tan,
     Tanh,
     Acot,
@@ -203,7 +207,6 @@ pub enum Function {
     ChisqTest,
     ConfidenceNorm,
     ConfidenceT,
-    // Correl,
     CovarianceP,
     CovarianceS,
     Devsq,
@@ -212,7 +215,7 @@ pub enum Function {
     FDistRT,
     FInv,
     FInvRT,
-    // FTest,
+    FTest,
     Fisher,
     FisherInv,
     // Forecast,
@@ -221,20 +224,18 @@ pub enum Function {
     GammaInv,
     GammaLn,
     GammaLnPrecise,
-    // Gauss,
-    // Growth,
-    // Harmean,
+    Gauss,
+    Harmean,
     HypGeomDist,
-    // Intercept,
-    // Kurt,
-    // Large,
+    Kurt,
+    Large,
     // Linest,
     // Logest,
     LogNormDist,
     LogNormInv,
-    // MaxA,
-    // Median,
-    // MinA,
+    MaxA,
+    Median,
+    MinA,
     // ModeMult,
     // ModeSingl,
     NegbinomDist,
@@ -254,19 +255,16 @@ pub enum Function {
     // Prob,
     // QuartileExc,
     // QuartileInc,
-    // RankAvg,
-    // RankEq,
-    // Rsq
-    // Skew,
-    // SkewP,
-    // Slope,
-    // Small,
+    RankAvg,
+    RankEq,
+    Skew,
+    SkewP,
+    Small,
     Standardize,
     StDevP,
     StDevS,
     Stdeva,
     Stdevpa,
-    // Steyx,
     TDist,
     TDist2T,
     TDistRT,
@@ -417,10 +415,16 @@ pub enum Function {
     Dvar,
     Dvarp,
     Dstdevp,
+
+    Correl,
+    Rsq,
+    Intercept,
+    Slope,
+    Steyx,
 }
 
 impl Function {
-    pub fn into_iter() -> IntoIter<Function, 324> {
+    pub fn into_iter() -> IntoIter<Function, 345> {
         [
             Function::And,
             Function::False,
@@ -497,6 +501,9 @@ impl Function {
             Function::Sum,
             Function::Sumif,
             Function::Sumifs,
+            Function::Sumx2my2,
+            Function::Sumx2py2,
+            Function::Sumxmy2,
             Function::Choose,
             Function::Column,
             Function::Columns,
@@ -711,6 +718,7 @@ impl Function {
             Function::FDistRT,
             Function::FInv,
             Function::FInvRT,
+            Function::FTest,
             Function::Fisher,
             Function::FisherInv,
             Function::Gamma,
@@ -746,6 +754,23 @@ impl Function {
             Function::VarA,
             Function::WeibullDist,
             Function::ZTest,
+            Function::Correl,
+            Function::Rsq,
+            Function::Intercept,
+            Function::Slope,
+            Function::Steyx,
+            Function::Large,
+            Function::Median,
+            Function::Small,
+            Function::RankAvg,
+            Function::RankEq,
+            Function::Skew,
+            Function::SkewP,
+            Function::Harmean,
+            Function::Gauss,
+            Function::Kurt,
+            Function::MaxA,
+            Function::MinA,
         ]
         .into_iter()
     }
@@ -837,6 +862,7 @@ impl Function {
             Function::FDistRT => "_xlfn.F.DIST.RT".to_string(),
             Function::FInv => "_xlfn.F.INV".to_string(),
             Function::FInvRT => "_xlfn.F.INV.RT".to_string(),
+            Function::FTest => "_xlfn.F.TEST".to_string(),
 
             Function::HypGeomDist => "_xlfn.HYPGEOM.DIST".to_string(),
 
@@ -867,6 +893,9 @@ impl Function {
 
             Function::WeibullDist => "_xlfn.WEIBULL.DIST".to_string(),
             Function::ZTest => "_xlfn.Z.TEST".to_string(),
+            Function::SkewP => "_xlfn.SKEW.P".to_string(),
+            Function::RankAvg => "_xlfn.RANK.AVG".to_string(),
+            Function::RankEq => "_xlfn.RANK.EQ".to_string(),
 
             _ => self.to_string(),
         }
@@ -1186,6 +1215,7 @@ impl Function {
             "F.DIST.RT" | "_XLFN.F.DIST.RT" => Some(Function::FDistRT),
             "F.INV" | "_XLFN.F.INV" => Some(Function::FInv),
             "F.INV.RT" | "_XLFN.F.INV.RT" => Some(Function::FInvRT),
+            "F.TEST" | "_XLFN.F.TEST" => Some(Function::FTest),
             "FISHER" => Some(Function::Fisher),
             "FISHERINV" => Some(Function::FisherInv),
             "GAMMA" | "_XLFN.GAMMA" => Some(Function::Gamma),
@@ -1221,6 +1251,28 @@ impl Function {
             "VARA" => Some(Function::VarA),
             "WEIBULL.DIST" | "_XLFN.WEIBULL.DIST" => Some(Function::WeibullDist),
             "Z.TEST" | "_XLFN.Z.TEST" => Some(Function::ZTest),
+            "SUMX2MY2" => Some(Function::Sumx2my2),
+            "SUMX2PY2" => Some(Function::Sumx2py2),
+            "SUMXMY2" => Some(Function::Sumxmy2),
+            "CORREL" => Some(Function::Correl),
+            "RSQ" => Some(Function::Rsq),
+            "INTERCEPT" => Some(Function::Intercept),
+            "SLOPE" => Some(Function::Slope),
+            "STEYX" => Some(Function::Steyx),
+
+            "SKEW.P" | "_XLFN.SKEW.P" => Some(Function::SkewP),
+            "SKEW" => Some(Function::Skew),
+            "KURT" => Some(Function::Kurt),
+            "HARMEAN" => Some(Function::Harmean),
+            "MEDIAN" => Some(Function::Median),
+            "GAUSS" => Some(Function::Gauss),
+
+            "MINA" => Some(Function::MinA),
+            "MAXA" => Some(Function::MaxA),
+            "SMALL" => Some(Function::Small),
+            "LARGE" => Some(Function::Large),
+            "RANK.EQ" | "_XLFN.RANK.EQ" => Some(Function::RankEq),
+            "RANK.AVG" | "_XLFN.RANK.AVG" => Some(Function::RankAvg),
 
             _ => None,
         }
@@ -1483,7 +1535,6 @@ impl fmt::Display for Function {
             Function::Combin => write!(f, "COMBIN"),
             Function::Combina => write!(f, "COMBINA"),
             Function::Sumsq => write!(f, "SUMSQ"),
-
             Function::N => write!(f, "N"),
             Function::Cell => write!(f, "CELL"),
             Function::Info => write!(f, "INFO"),
@@ -1500,7 +1551,6 @@ impl fmt::Display for Function {
             Function::Dvar => write!(f, "DVAR"),
             Function::Dvarp => write!(f, "DVARP"),
             Function::Dstdevp => write!(f, "DSTDEVP"),
-
             Function::BetaDist => write!(f, "BETA.DIST"),
             Function::BetaInv => write!(f, "BETA.INV"),
             Function::BinomDist => write!(f, "BINOM.DIST"),
@@ -1523,6 +1573,7 @@ impl fmt::Display for Function {
             Function::FInvRT => write!(f, "F.INV.RT"),
             Function::Fisher => write!(f, "FISHER"),
             Function::FisherInv => write!(f, "FISHERINV"),
+            Function::FTest => write!(f, "F.TEST"),
             Function::Gamma => write!(f, "GAMMA"),
             Function::GammaDist => write!(f, "GAMMA.DIST"),
             Function::GammaInv => write!(f, "GAMMA.INV"),
@@ -1556,6 +1607,27 @@ impl fmt::Display for Function {
             Function::VarA => write!(f, "VARA"),
             Function::WeibullDist => write!(f, "WEIBULL.DIST"),
             Function::ZTest => write!(f, "Z.TEST"),
+            Function::Sumx2my2 => write!(f, "SUMX2MY2"),
+            Function::Sumx2py2 => write!(f, "SUMX2PY2"),
+            Function::Sumxmy2 => write!(f, "SUMXMY2"),
+            Function::Correl => write!(f, "CORREL"),
+            Function::Rsq => write!(f, "RSQ"),
+            Function::Intercept => write!(f, "INTERCEPT"),
+            Function::Slope => write!(f, "SLOPE"),
+            Function::Steyx => write!(f, "STEYX"),
+            // new ones
+            Function::Gauss => write!(f, "GAUSS"),
+            Function::Harmean => write!(f, "HARMEAN"),
+            Function::Kurt => write!(f, "KURT"),
+            Function::Large => write!(f, "LARGE"),
+            Function::MaxA => write!(f, "MAXA"),
+            Function::Median => write!(f, "MEDIAN"),
+            Function::MinA => write!(f, "MINA"),
+            Function::RankAvg => write!(f, "RANK.AVG"),
+            Function::RankEq => write!(f, "RANK.EQ"),
+            Function::Skew => write!(f, "SKEW"),
+            Function::SkewP => write!(f, "SKEW.P"),
+            Function::Small => write!(f, "SMALL"),
         }
     }
 }
@@ -1875,6 +1947,7 @@ impl Model {
             Function::FInvRT => self.fn_f_inv_rt(args, cell),
             Function::Fisher => self.fn_fisher(args, cell),
             Function::FisherInv => self.fn_fisher_inv(args, cell),
+            Function::FTest => self.fn_f_test(args, cell),
             Function::Gamma => self.fn_gamma(args, cell),
             Function::GammaDist => self.fn_gamma_dist(args, cell),
             Function::GammaInv => self.fn_gamma_inv(args, cell),
@@ -1908,6 +1981,26 @@ impl Model {
             Function::VarA => self.fn_vara(args, cell),
             Function::WeibullDist => self.fn_weibull_dist(args, cell),
             Function::ZTest => self.fn_z_test(args, cell),
+            Function::Sumx2my2 => self.fn_sumx2my2(args, cell),
+            Function::Sumx2py2 => self.fn_sumx2py2(args, cell),
+            Function::Sumxmy2 => self.fn_sumxmy2(args, cell),
+            Function::Correl => self.fn_correl(args, cell),
+            Function::Rsq => self.fn_rsq(args, cell),
+            Function::Intercept => self.fn_intercept(args, cell),
+            Function::Slope => self.fn_slope(args, cell),
+            Function::Steyx => self.fn_steyx(args, cell),
+            Function::Gauss => self.fn_gauss(args, cell),
+            Function::Harmean => self.fn_harmean(args, cell),
+            Function::Kurt => self.fn_kurt(args, cell),
+            Function::Large => self.fn_large(args, cell),
+            Function::MaxA => self.fn_maxa(args, cell),
+            Function::Median => self.fn_median(args, cell),
+            Function::MinA => self.fn_mina(args, cell),
+            Function::RankAvg => self.fn_rank_avg(args, cell),
+            Function::RankEq => self.fn_rank_eq(args, cell),
+            Function::Skew => self.fn_skew(args, cell),
+            Function::SkewP => self.fn_skew_p(args, cell),
+            Function::Small => self.fn_small(args, cell),
         }
     }
 }

base/src/functions/statistical/chisq.rs

@@ -6,13 +6,6 @@ use crate::{
     calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
 };
 
-// Helper to check if two shapes are the same or compatible 1D shapes
-pub(crate) fn is_same_shape_or_1d(rows1: i32, cols1: i32, rows2: i32, cols2: i32) -> bool {
-    (rows1 == rows2 && cols1 == cols2)
-        || (rows1 == 1 && cols2 == 1 && cols1 == rows2)
-        || (rows2 == 1 && cols1 == 1 && cols2 == rows1)
-}
-
 impl Model {
     // CHISQ.DIST(x, deg_freedom, cumulative)
     pub(crate) fn fn_chisq_dist(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
@@ -310,171 +303,10 @@ impl Model {
 
     // CHISQ.TEST(actual_range, expected_range)
     pub(crate) fn fn_chisq_test(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
-        if args.len() != 2 {
-            return CalcResult::new_args_number_error(cell);
-        }
-        let actual_range = self.evaluate_node_in_context(&args[0], cell);
-        let expected_range = self.evaluate_node_in_context(&args[1], cell);
-
-        let (width, height, values_left, values_right) = match (actual_range, expected_range) {
-            (
-                CalcResult::Range {
-                    left: l1,
-                    right: r1,
-                },
-                CalcResult::Range {
-                    left: l2,
-                    right: r2,
-                },
-            ) => {
-                if l1.sheet != l2.sheet {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Ranges are in different sheets".to_string(),
-                    );
-                }
-                let rows1 = r1.row - l1.row + 1;
-                let cols1 = r1.column - l1.column + 1;
-                let rows2 = r2.row - l2.row + 1;
-                let cols2 = r2.column - l2.column + 1;
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Ranges must be of the same shape".to_string(),
-                    );
-                }
-                let values_left = match self.values_from_range(l1, r1) {
-                    Err(error) => {
-                        return error;
-                    }
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_range(l2, r2) {
-                    Err(error) => {
-                        return error;
-                    }
-                    Ok(v) => v,
-                };
-                (rows1, cols1, values_left, values_right)
-            }
-            (
-                CalcResult::Array(left),
-                CalcResult::Range {
-                    left: l2,
-                    right: r2,
-                },
-            ) => {
-                let rows2 = r2.row - l2.row + 1;
-                let cols2 = r2.column - l2.column + 1;
-
-                let rows1 = left.len() as i32;
-                let cols1 = if rows1 > 0 { left[0].len() as i32 } else { 0 };
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Array and range must be of the same shape".to_string(),
-                    );
-                }
-                let values_left = match self.values_from_array(left) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in first array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_range(l2, r2) {
-                    Err(error) => {
-                        return error;
-                    }
-                    Ok(v) => v,
-                };
-                (rows2, cols2, values_left, values_right)
-            }
-            (
-                CalcResult::Range {
-                    left: l1,
-                    right: r1,
-                },
-                CalcResult::Array(right),
-            ) => {
-                let rows1 = r1.row - l1.row + 1;
-                let cols1 = r1.column - l1.column + 1;
-
-                let rows2 = right.len() as i32;
-                let cols2 = if rows2 > 0 { right[0].len() as i32 } else { 0 };
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Range and array must be of the same shape".to_string(),
-                    );
-                }
-                let values_left = match self.values_from_range(l1, r1) {
-                    Err(error) => {
-                        return error;
-                    }
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_array(right) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in second array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-                (rows1, cols1, values_left, values_right)
-            }
-            (CalcResult::Array(left), CalcResult::Array(right)) => {
-                let rows1 = left.len() as i32;
-                let rows2 = right.len() as i32;
-                let cols1 = if rows1 > 0 { left[0].len() as i32 } else { 0 };
-                let cols2 = if rows2 > 0 { right[0].len() as i32 } else { 0 };
-
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Arrays must be of the same shape".to_string(),
-                    );
-                }
-                let values_left = match self.values_from_array(left) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in first array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_array(right) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in second array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-                (rows1, cols1, values_left, values_right)
-            }
-            _ => {
-                return CalcResult::new_error(
-                    Error::VALUE,
-                    cell,
-                    "Both arguments must be ranges or arrays".to_string(),
-                );
-            }
+        let (width, height, values_left, values_right) = match self.fn_get_two_matrices(args, cell)
+        {
+            Ok(v) => v,
+            Err(r) => return r,
         };
 
         let mut values = Vec::with_capacity(values_left.len());

base/src/functions/statistical/correl.rs

@@ -0,0 +1,227 @@
+use crate::expressions::types::CellReferenceIndex;
+use crate::{
+    calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
+};
+
+impl Model {
+    // CORREL(array1, array2) - Returns the correlation coefficient of two data sets
+    pub(crate) fn fn_correl(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let (_, _, values_left, values_right) = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(e) => return e,
+        };
+
+        let mut n = 0.0;
+        let mut sum_x = 0.0;
+        let mut sum_y = 0.0;
+        let mut sum_x2 = 0.0;
+        let mut sum_y2 = 0.0;
+        let mut sum_xy = 0.0;
+
+        for (x_opt, y_opt) in values_left.into_iter().zip(values_right.into_iter()) {
+            if let (Some(x), Some(y)) = (x_opt, y_opt) {
+                n += 1.0;
+                sum_x += x;
+                sum_y += y;
+                sum_x2 += x * x;
+                sum_y2 += y * y;
+                sum_xy += x * y;
+            }
+        }
+
+        // Need at least 2 valid pairs
+        if n < 2.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "CORREL requires at least two numeric data points in each range".to_string(),
+            );
+        }
+
+        let num = n * sum_xy - sum_x * sum_y;
+        let denom_x = n * sum_x2 - sum_x * sum_x;
+        let denom_y = n * sum_y2 - sum_y * sum_y;
+        let denom = (denom_x * denom_y).sqrt();
+
+        if denom == 0.0 || !denom.is_finite() {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "Division by zero in CORREL".to_string(),
+            );
+        }
+
+        let r = num / denom;
+        CalcResult::Number(r)
+    }
+
+    // SLOPE(known_y's, known_x's) - Returns the slope of the linear regression line
+    pub(crate) fn fn_slope(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let (_rows, _cols, values_y, values_x) = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(e) => return e,
+        };
+
+        let mut n = 0.0;
+        let mut sum_x = 0.0;
+        let mut sum_y = 0.0;
+        let mut sum_x2 = 0.0;
+        let mut sum_xy = 0.0;
+
+        let len = values_y.len().min(values_x.len());
+        for i in 0..len {
+            if let (Some(y), Some(x)) = (values_y[i], values_x[i]) {
+                n += 1.0;
+                sum_x += x;
+                sum_y += y;
+                sum_x2 += x * x;
+                sum_xy += x * y;
+            }
+        }
+
+        if n < 2.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "SLOPE requires at least two numeric data points".to_string(),
+            );
+        }
+
+        let denom = n * sum_x2 - sum_x * sum_x;
+        if denom == 0.0 || !denom.is_finite() {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "Division by zero in SLOPE".to_string(),
+            );
+        }
+
+        let num = n * sum_xy - sum_x * sum_y;
+        let slope = num / denom;
+
+        CalcResult::Number(slope)
+    }
+
+    // INTERCEPT(known_y's, known_x's) - Returns the y-intercept of the linear regression line
+    pub(crate) fn fn_intercept(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let (_rows, _cols, values_y, values_x) = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(e) => return e,
+        };
+
+        let mut n = 0.0;
+        let mut sum_x = 0.0;
+        let mut sum_y = 0.0;
+        let mut sum_x2 = 0.0;
+        let mut sum_xy = 0.0;
+
+        let len = values_y.len().min(values_x.len());
+        for i in 0..len {
+            if let (Some(y), Some(x)) = (values_y[i], values_x[i]) {
+                n += 1.0;
+                sum_x += x;
+                sum_y += y;
+                sum_x2 += x * x;
+                sum_xy += x * y;
+            }
+        }
+
+        if n < 2.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "INTERCEPT requires at least two numeric data points".to_string(),
+            );
+        }
+
+        let denom = n * sum_x2 - sum_x * sum_x;
+        if denom == 0.0 || !denom.is_finite() {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "Division by zero in INTERCEPT".to_string(),
+            );
+        }
+
+        let num = n * sum_xy - sum_x * sum_y;
+        let slope = num / denom;
+        let intercept = (sum_y - slope * sum_x) / n;
+
+        CalcResult::Number(intercept)
+    }
+
+    // STEYX(known_y's, known_x's) - Returns the standard error of the predicted y-values
+    pub(crate) fn fn_steyx(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let (_rows, _cols, values_y, values_x) = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(e) => return e,
+        };
+
+        let mut n = 0.0;
+        let mut sum_x = 0.0;
+        let mut sum_y = 0.0;
+        let mut sum_x2 = 0.0;
+        let mut sum_xy = 0.0;
+
+        // We need the actual pairs again later for residuals
+        let mut pairs: Vec<(f64, f64)> = Vec::new();
+
+        let len = values_y.len().min(values_x.len());
+        for i in 0..len {
+            if let (Some(y), Some(x)) = (values_y[i], values_x[i]) {
+                n += 1.0;
+                sum_x += x;
+                sum_y += y;
+                sum_x2 += x * x;
+                sum_xy += x * y;
+                pairs.push((x, y));
+            }
+        }
+
+        // Need at least 3 points for STEYX (n - 2 in denominator)
+        if n < 3.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "STEYX requires at least three numeric data points".to_string(),
+            );
+        }
+
+        let denom = n * sum_x2 - sum_x * sum_x;
+        if denom == 0.0 || !denom.is_finite() {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "Division by zero in STEYX".to_string(),
+            );
+        }
+
+        let num = n * sum_xy - sum_x * sum_y;
+        let slope = num / denom;
+        let intercept = (sum_y - slope * sum_x) / n;
+
+        // Sum of squared residuals: Σ (y - ŷ)^2, ŷ = intercept + slope * x
+        let mut sse = 0.0;
+        for (x, y) in pairs {
+            let y_hat = intercept + slope * x;
+            let diff = y - y_hat;
+            sse += diff * diff;
+        }
+
+        let dof = n - 2.0;
+        if dof <= 0.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "STEYX has non-positive degrees of freedom".to_string(),
+            );
+        }
+
+        let sey = (sse / dof).sqrt();
+        if !sey.is_finite() {
+            return CalcResult::new_error(Error::DIV, cell, "Numerical error in STEYX".to_string());
+        }
+
+        CalcResult::Number(sey)
+    }
+}

base/src/functions/statistical/count_and_average.rs

@@ -1,3 +1,5 @@
+use std::cmp::Ordering;
+
 use crate::constants::{LAST_COLUMN, LAST_ROW};
 use crate::expressions::parser::ArrayNode;
 use crate::expressions::types::CellReferenceIndex;
@@ -6,77 +8,219 @@ use crate::{
 };
 
 impl Model {
-    pub(crate) fn fn_average(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
-        if args.is_empty() {
-            return CalcResult::new_args_number_error(cell);
-        }
-        let mut count = 0.0;
-        let mut sum = 0.0;
+    fn for_each_value<F>(
+        &mut self,
+        args: &[Node],
+        cell: CellReferenceIndex,
+        mut f: F,
+    ) -> Result<(), CalcResult>
+    where
+        F: FnMut(f64),
+    {
         for arg in args {
             match self.evaluate_node_in_context(arg, cell) {
                 CalcResult::Number(value) => {
-                    count += 1.0;
-                    sum += value;
+                    f(value);
                 }
-                CalcResult::Boolean(b) => {
-                    if let Node::ReferenceKind { .. } = arg {
-                    } else {
-                        sum += if b { 1.0 } else { 0.0 };
-                        count += 1.0;
+                CalcResult::Boolean(value) => {
+                    if !matches!(arg, Node::ReferenceKind { .. }) {
+                        f(if value { 1.0 } else { 0.0 });
+                    }
+                }
+                CalcResult::String(value) => {
+                    if !matches!(arg, Node::ReferenceKind { .. }) {
+                        if let Some(parsed) = self.cast_number(&value) {
+                            f(parsed);
+                        } else {
+                            return Err(CalcResult::new_error(
+                                Error::VALUE,
+                                cell,
+                                "Argument cannot be cast into number".to_string(),
+                            ));
+                        }
+                    }
+                }
+                CalcResult::Array(array) => {
+                    for row in array {
+                        for value in row {
+                            match value {
+                                ArrayNode::Number(value) => {
+                                    f(value);
+                                }
+                                ArrayNode::Boolean(b) => {
+                                    f(if b { 1.0 } else { 0.0 });
+                                }
+                                ArrayNode::Error(error) => {
+                                    return Err(CalcResult::Error {
+                                        error,
+                                        origin: cell,
+                                        message: "Error in array".to_string(),
+                                    });
+                                }
+                                _ => {
+                                    // ignore non-numeric
+                                }
+                            }
+                        }
                     }
                 }
                 CalcResult::Range { left, right } => {
                     if left.sheet != right.sheet {
-                        return CalcResult::new_error(
+                        return Err(CalcResult::new_error(
                             Error::VALUE,
                             cell,
                             "Ranges are in different sheets".to_string(),
-                        );
+                        ));
                     }
-                    for row in left.row..(right.row + 1) {
-                        for column in left.column..(right.column + 1) {
+
+                    for row in left.row..=right.row {
+                        for column in left.column..=right.column {
                             match self.evaluate_cell(CellReferenceIndex {
                                 sheet: left.sheet,
                                 row,
                                 column,
                             }) {
                                 CalcResult::Number(value) => {
-                                    count += 1.0;
-                                    sum += value;
+                                    f(value);
                                 }
-                                error @ CalcResult::Error { .. } => return error,
+                                error @ CalcResult::Error { .. } => return Err(error),
                                 CalcResult::Range { .. } => {
-                                    return CalcResult::new_error(
+                                    return Err(CalcResult::new_error(
                                         Error::ERROR,
                                         cell,
                                         "Unexpected Range".to_string(),
-                                    );
+                                    ));
                                 }
                                 _ => {}
                             }
                         }
                     }
                 }
-                error @ CalcResult::Error { .. } => return error,
-                CalcResult::String(s) => {
-                    if let Node::ReferenceKind { .. } = arg {
-                        // Do nothing
-                    } else if let Ok(t) = s.parse::<f64>() {
-                        sum += t;
-                        count += 1.0;
-                    } else {
-                        return CalcResult::Error {
-                            error: Error::VALUE,
-                            origin: cell,
-                            message: "Argument cannot be cast into number".to_string(),
-                        };
+                error @ CalcResult::Error { .. } => return Err(error),
+                // Everything else is ignored
+                _ => {}
+            }
+        }
+
+        Ok(())
+    }
+
+    fn for_each_value_a<F>(
+        &mut self,
+        args: &[Node],
+        cell: CellReferenceIndex,
+        mut f: F,
+    ) -> Result<(), CalcResult>
+    where
+        F: FnMut(f64),
+    {
+        for arg in args {
+            match self.evaluate_node_in_context(arg, cell) {
+                CalcResult::Number(value) => {
+                    f(value);
+                }
+                CalcResult::Boolean(value) => {
+                    if !matches!(arg, Node::ReferenceKind { .. }) {
+                        f(if value { 1.0 } else { 0.0 });
                     }
                 }
-                _ => {
-                    // Ignore everything else
+                CalcResult::String(value) => {
+                    if !matches!(arg, Node::ReferenceKind { .. }) {
+                        if let Some(parsed) = self.cast_number(&value) {
+                            f(parsed);
+                        } else {
+                            return Err(CalcResult::new_error(
+                                Error::VALUE,
+                                cell,
+                                "Argument cannot be cast into number".to_string(),
+                            ));
+                        }
+                    }
                 }
-            };
+                CalcResult::Array(array) => {
+                    for row in array {
+                        for value in row {
+                            match value {
+                                ArrayNode::Number(value) => {
+                                    f(value);
+                                }
+                                ArrayNode::Boolean(b) => {
+                                    f(if b { 1.0 } else { 0.0 });
+                                }
+                                ArrayNode::String(_) => {
+                                    f(0.0);
+                                }
+                                ArrayNode::Error(error) => {
+                                    return Err(CalcResult::Error {
+                                        error,
+                                        origin: cell,
+                                        message: "Error in array".to_string(),
+                                    });
+                                }
+                            }
+                        }
+                    }
+                }
+                CalcResult::Range { left, right } => {
+                    if left.sheet != right.sheet {
+                        return Err(CalcResult::new_error(
+                            Error::VALUE,
+                            cell,
+                            "Ranges are in different sheets".to_string(),
+                        ));
+                    }
+
+                    for row in left.row..=right.row {
+                        for column in left.column..=right.column {
+                            match self.evaluate_cell(CellReferenceIndex {
+                                sheet: left.sheet,
+                                row,
+                                column,
+                            }) {
+                                CalcResult::Number(value) => {
+                                    f(value);
+                                }
+                                CalcResult::Boolean(b) => {
+                                    f(if b { 1.0 } else { 0.0 });
+                                }
+                                CalcResult::String(_) => {
+                                    f(0.0);
+                                }
+                                error @ CalcResult::Error { .. } => return Err(error),
+                                CalcResult::Range { .. } => {
+                                    return Err(CalcResult::new_error(
+                                        Error::ERROR,
+                                        cell,
+                                        "Unexpected Range".to_string(),
+                                    ));
+                                }
+                                _ => {}
+                            }
+                        }
+                    }
+                }
+                error @ CalcResult::Error { .. } => return Err(error),
+                // Everything else is ignored
+                _ => {}
+            }
         }
+
+        Ok(())
+    }
+
+    pub(crate) fn fn_average(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let mut count = 0.0;
+        let mut sum = 0.0;
+        if let Err(e) = self.for_each_value(args, cell, |f| {
+            count += 1.0;
+            sum += f;
+        }) {
+            return e;
+        }
+
         if count == 0.0 {
             return CalcResult::Error {
                 error: Error::DIV,
@@ -86,6 +230,7 @@ impl Model {
         }
         CalcResult::Number(sum / count)
     }
+
     pub(crate) fn fn_averagea(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
         if args.is_empty() {
             return CalcResult::new_args_number_error(cell);
@@ -443,4 +588,484 @@ impl Model {
 
         CalcResult::Number(sum_abs_dev / n)
     }
+
+    pub(crate) fn fn_median(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let mut values: Vec<f64> = Vec::new();
+        if let Err(e) = self.for_each_value(args, cell, |f| values.push(f)) {
+            return e;
+        }
+
+        if values.is_empty() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "No numeric values for MEDIAN".to_string(),
+            };
+        }
+
+        values.sort_by(|a, b| a.partial_cmp(b).unwrap_or(Ordering::Equal));
+
+        let n = values.len();
+        let median = if n % 2 == 1 {
+            // odd
+            values[n / 2]
+        } else {
+            // even: average of the two middle values
+            let a = values[(n / 2) - 1];
+            let b = values[n / 2];
+            (a + b) / 2.0
+        };
+
+        CalcResult::Number(median)
+    }
+
+    pub(crate) fn fn_harmean(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let mut values: Vec<f64> = Vec::new();
+        if let Err(e) = self.for_each_value(args, cell, |f| values.push(f)) {
+            return e;
+        }
+
+        if values.is_empty() {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "Division by Zero".to_string(),
+            };
+        }
+
+        // Excel HARMEAN: all values must be > 0
+        if values.iter().any(|&v| v <= 0.0) {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "HARMEAN requires strictly positive values".to_string(),
+            };
+        }
+
+        let n = values.len() as f64;
+        let sum_recip: f64 = values.iter().map(|v| 1.0 / v).sum();
+
+        if sum_recip == 0.0 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "Division by Zero".to_string(),
+            };
+        }
+
+        CalcResult::Number(n / sum_recip)
+    }
+
+    pub(crate) fn fn_mina(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let mut mina: Option<f64> = None;
+        if let Err(e) = self.for_each_value_a(args, cell, |f| {
+            if let Some(m) = mina {
+                mina = Some(m.min(f));
+            } else {
+                mina = Some(f);
+            }
+        }) {
+            return e;
+        }
+        if let Some(mina) = mina {
+            CalcResult::Number(mina)
+        } else {
+            CalcResult::Error {
+                error: Error::VALUE,
+                origin: cell,
+                message: "No numeric values for MINA".to_string(),
+            }
+        }
+    }
+
+    pub(crate) fn fn_maxa(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let mut maxa: Option<f64> = None;
+        if let Err(e) = self.for_each_value_a(args, cell, |f| {
+            if let Some(m) = maxa {
+                maxa = Some(m.max(f));
+            } else {
+                maxa = Some(f);
+            }
+        }) {
+            return e;
+        }
+        if let Some(maxa) = maxa {
+            CalcResult::Number(maxa)
+        } else {
+            CalcResult::Error {
+                error: Error::VALUE,
+                origin: cell,
+                message: "No numeric values for MAXA".to_string(),
+            }
+        }
+    }
+
+    pub(crate) fn fn_skew(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        // Sample skewness (Excel SKEW)
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let mut values: Vec<f64> = Vec::new();
+        if let Err(e) = self.for_each_value(args, cell, |f| values.push(f)) {
+            return e;
+        }
+
+        let n = values.len();
+        if n < 3 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "SKEW requires at least 3 data points".to_string(),
+            };
+        }
+
+        let n_f = n as f64;
+        let mean = values.iter().sum::<f64>() / n_f;
+
+        let mut m2 = 0.0;
+        for &x in &values {
+            let d = x - mean;
+            m2 += d * d;
+        }
+
+        if m2 == 0.0 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "Zero variance in SKEW".to_string(),
+            };
+        }
+
+        let s = (m2 / (n_f - 1.0)).sqrt();
+
+        let mut sum_cubed = 0.0;
+        for &x in &values {
+            let z = (x - mean) / s;
+            sum_cubed += z * z * z;
+        }
+
+        let skew = (n_f / ((n_f - 1.0) * (n_f - 2.0))) * sum_cubed;
+        CalcResult::Number(skew)
+    }
+
+    pub(crate) fn fn_skew_p(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        // Population skewness (Excel SKEW.P)
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let mut values: Vec<f64> = Vec::new();
+        if let Err(e) = self.for_each_value(args, cell, |f| values.push(f)) {
+            return e;
+        }
+
+        let n = values.len();
+        if n < 2 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "SKEW.P requires at least 2 data points".to_string(),
+            };
+        }
+
+        let n_f = n as f64;
+        let mean = values.iter().sum::<f64>() / n_f;
+
+        let mut m2 = 0.0;
+        for &x in &values {
+            let d = x - mean;
+            m2 += d * d;
+        }
+
+        if m2 == 0.0 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "Zero variance in SKEW.P".to_string(),
+            };
+        }
+
+        let sigma = (m2 / n_f).sqrt();
+
+        let mut sum_cubed = 0.0;
+        for &x in &values {
+            let z = (x - mean) / sigma;
+            sum_cubed += z * z * z;
+        }
+
+        let skew_p = sum_cubed / n_f;
+        CalcResult::Number(skew_p)
+    }
+
+    pub(crate) fn fn_kurt(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let mut values: Vec<f64> = Vec::new();
+        if let Err(e) = self.for_each_value(args, cell, |f| values.push(f)) {
+            return e;
+        }
+
+        let n = values.len();
+        if n < 4 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "KURT requires at least 4 data points".to_string(),
+            };
+        }
+
+        let n_f = n as f64;
+        let mean = values.iter().sum::<f64>() / n_f;
+
+        let mut m2 = 0.0;
+        for &x in &values {
+            let d = x - mean;
+            m2 += d * d;
+        }
+
+        if m2 == 0.0 {
+            return CalcResult::Error {
+                error: Error::DIV,
+                origin: cell,
+                message: "Zero variance in KURT".to_string(),
+            };
+        }
+
+        let s = (m2 / (n_f - 1.0)).sqrt();
+
+        let mut sum_fourth = 0.0;
+        for &x in &values {
+            let z = (x - mean) / s;
+            sum_fourth += z * z * z * z;
+        }
+
+        let term1 = (n_f * (n_f + 1.0)) / ((n_f - 1.0) * (n_f - 2.0) * (n_f - 3.0)) * sum_fourth;
+        let term2 = 3.0 * (n_f - 1.0) * (n_f - 1.0) / ((n_f - 2.0) * (n_f - 3.0));
+
+        let kurt = term1 - term2;
+        CalcResult::Number(kurt)
+    }
+
+    pub(crate) fn fn_large(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.len() != 2 {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let values = match self.evaluate_node_in_context(&args[0], cell) {
+            CalcResult::Array(array) => match self.values_from_array(array) {
+                Ok(v) => v,
+                Err(e) => {
+                    return CalcResult::Error {
+                        error: Error::VALUE,
+                        origin: cell,
+                        message: format!("Unsupported array argument: {}", e),
+                    }
+                }
+            },
+            CalcResult::Range { left, right } => match self.values_from_range(left, right) {
+                Ok(v) => v,
+                Err(e) => return e,
+            },
+            CalcResult::Boolean(value) => {
+                if !matches!(args[0], Node::ReferenceKind { .. }) {
+                    vec![Some(if value { 1.0 } else { 0.0 })]
+                } else {
+                    return CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    };
+                }
+            }
+            CalcResult::Number(value) => {
+                if !matches!(args[0], Node::ReferenceKind { .. }) {
+                    vec![Some(value)]
+                } else {
+                    return CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    };
+                }
+            }
+            CalcResult::String(value) => {
+                if !matches!(args[0], Node::ReferenceKind { .. }) {
+                    if let Some(parsed) = self.cast_number(&value) {
+                        vec![Some(parsed)]
+                    } else {
+                        return CalcResult::Error {
+                            error: Error::VALUE,
+                            origin: cell,
+                            message: "Unsupported argument type".to_string(),
+                        };
+                    }
+                } else {
+                    return CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    };
+                }
+            }
+            _ => {
+                return CalcResult::Error {
+                    error: Error::NIMPL,
+                    origin: cell,
+                    message: "Unsupported argument type".to_string(),
+                }
+            }
+        };
+        let k = match self.get_number_no_bools(&args[1], cell) {
+            Ok(f) => f.trunc(),
+            Err(s) => return s,
+        };
+        if k < 1.0 {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "K must be >= 1".to_string(),
+            };
+        }
+        let mut numeric_values: Vec<f64> = values.into_iter().flatten().collect();
+        if numeric_values.is_empty() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "No numeric values for LARGE".to_string(),
+            };
+        }
+        numeric_values.sort_by(|a, b| b.partial_cmp(a).unwrap_or(Ordering::Equal));
+        let k_usize = k as usize;
+        if k_usize > numeric_values.len() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "K is larger than the number of data points".to_string(),
+            };
+        }
+        CalcResult::Number(numeric_values[k_usize - 1])
+    }
+
+    pub(crate) fn fn_small(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.len() != 2 {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let values = match self.evaluate_node_in_context(&args[0], cell) {
+            CalcResult::Array(array) => match self.values_from_array(array) {
+                Ok(v) => v,
+                Err(e) => {
+                    return CalcResult::Error {
+                        error: Error::VALUE,
+                        origin: cell,
+                        message: format!("Unsupported array argument: {}", e),
+                    }
+                }
+            },
+            CalcResult::Range { left, right } => match self.values_from_range(left, right) {
+                Ok(v) => v,
+                Err(e) => return e,
+            },
+            CalcResult::Boolean(value) => {
+                if !matches!(args[0], Node::ReferenceKind { .. }) {
+                    vec![Some(if value { 1.0 } else { 0.0 })]
+                } else {
+                    return CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    };
+                }
+            }
+            CalcResult::Number(value) => {
+                if !matches!(args[0], Node::ReferenceKind { .. }) {
+                    vec![Some(value)]
+                } else {
+                    return CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    };
+                }
+            }
+            CalcResult::String(value) => {
+                if !matches!(args[0], Node::ReferenceKind { .. }) {
+                    if let Some(parsed) = self.cast_number(&value) {
+                        vec![Some(parsed)]
+                    } else {
+                        return CalcResult::Error {
+                            error: Error::VALUE,
+                            origin: cell,
+                            message: "Unsupported argument type".to_string(),
+                        };
+                    }
+                } else {
+                    return CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    };
+                }
+            }
+            _ => {
+                return CalcResult::Error {
+                    error: Error::NIMPL,
+                    origin: cell,
+                    message: "Unsupported argument type".to_string(),
+                }
+            }
+        };
+
+        let k = match self.get_number_no_bools(&args[1], cell) {
+            Ok(f) => f.trunc(),
+            Err(s) => return s,
+        };
+
+        if k < 1.0 {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "K must be >= 1".to_string(),
+            };
+        }
+
+        let mut numeric_values: Vec<f64> = values.into_iter().flatten().collect();
+        if numeric_values.is_empty() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "No numeric values for SMALL".to_string(),
+            };
+        }
+
+        // For SMALL, sort ascending
+        numeric_values.sort_by(|a, b| a.partial_cmp(b).unwrap_or(Ordering::Equal));
+
+        let k_usize = k as usize;
+        if k_usize > numeric_values.len() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "K is larger than the number of data points".to_string(),
+            };
+        }
+
+        CalcResult::Number(numeric_values[k_usize - 1])
+    }
 }

base/src/functions/statistical/fisher.rs

@@ -1,6 +1,7 @@
 use statrs::distribution::{Continuous, ContinuousCDF, FisherSnedecor};
 
 use crate::expressions::types::CellReferenceIndex;
+use crate::functions::statistical::t_dist::sample_var;
 use crate::{
     calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
 };
@@ -296,4 +297,122 @@ impl Model {
 
         CalcResult::Number(x)
     }
+
+    // F.TEST(array1, array2)
+    pub(crate) fn fn_f_test(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.len() != 2 {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let values1_opts = match self.evaluate_node_in_context(&args[0], cell) {
+            CalcResult::Range { left, right } => match self.values_from_range(left, right) {
+                Ok(v) => v,
+                Err(error) => return error,
+            },
+            CalcResult::Array(a) => match self.values_from_array(a) {
+                Ok(v) => v,
+                Err(error) => {
+                    return CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        format!("Error in first array: {:?}", error),
+                    );
+                }
+            },
+            _ => {
+                return CalcResult::new_error(
+                    Error::VALUE,
+                    cell,
+                    "First argument must be a range or array".to_string(),
+                );
+            }
+        };
+
+        // Get second sample as Vec<Option<f64>>
+        let values2_opts = match self.evaluate_node_in_context(&args[1], cell) {
+            CalcResult::Range { left, right } => match self.values_from_range(left, right) {
+                Ok(v) => v,
+                Err(error) => return error,
+            },
+            CalcResult::Array(a) => match self.values_from_array(a) {
+                Ok(v) => v,
+                Err(error) => {
+                    return CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        format!("Error in second array: {:?}", error),
+                    );
+                }
+            },
+            _ => {
+                return CalcResult::new_error(
+                    Error::VALUE,
+                    cell,
+                    "Second argument must be a range or array".to_string(),
+                );
+            }
+        };
+
+        let values1: Vec<f64> = values1_opts.into_iter().flatten().collect();
+        let values2: Vec<f64> = values2_opts.into_iter().flatten().collect();
+
+        let n1 = values1.len();
+        let n2 = values2.len();
+
+        // If fewer than 2 numeric values in either sample -> #DIV/0!
+        if n1 < 2 || n2 < 2 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "F.TEST requires at least two numeric values in each sample".to_string(),
+            );
+        }
+
+        let v1 = sample_var(&values1);
+        let v2 = sample_var(&values2);
+
+        if v1 <= 0.0 || v2 <= 0.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "Variance of one sample is zero in F.TEST".to_string(),
+            );
+        }
+
+        // F ratio: larger variance / smaller variance
+        let mut f = v1 / v2;
+        let mut df1 = (n1 - 1) as f64;
+        let mut df2 = (n2 - 1) as f64;
+
+        if f < 1.0 {
+            f = 1.0 / f;
+            std::mem::swap(&mut df1, &mut df2);
+        }
+
+        let dist = match FisherSnedecor::new(df1, df2) {
+            Ok(d) => d,
+            Err(_) => {
+                return CalcResult::new_error(
+                    Error::NUM,
+                    cell,
+                    "Invalid parameters for F distribution in F.TEST".to_string(),
+                );
+            }
+        };
+
+        // One-tailed right-tail probability
+        let tail = 1.0 - dist.cdf(f);
+        // F.TEST is two-tailed: p = 2 * tail (with F >= 1)
+        let mut p = 2.0 * tail;
+
+        // Clamp tiny FP noise
+        if p < 0.0 && p > -1e-15 {
+            p = 0.0;
+        }
+        if p > 1.0 && p < 1.0 + 1e-15 {
+            p = 1.0;
+        }
+
+        CalcResult::Number(p)
+    }
 }

base/src/functions/statistical/gauss.rs

@@ -0,0 +1,39 @@
+use statrs::distribution::{ContinuousCDF, Normal};
+
+use crate::expressions::token::Error;
+use crate::expressions::types::CellReferenceIndex;
+use crate::{calc_result::CalcResult, expressions::parser::Node, model::Model};
+
+impl Model {
+    pub(crate) fn fn_gauss(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.len() != 1 {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let z = match self.get_number_no_bools(&args[0], cell) {
+            Ok(f) => f,
+            Err(s) => return s,
+        };
+        let dist = match Normal::new(0.0, 1.0) {
+            Ok(d) => d,
+            Err(_) => {
+                return CalcResult::Error {
+                    error: Error::ERROR,
+                    origin: cell,
+                    message: "Failed to construct standard normal distribution".to_string(),
+                }
+            }
+        };
+
+        let result = dist.cdf(z) - 0.5;
+
+        if !result.is_finite() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "Invalid result for GAUSS".to_string(),
+            };
+        }
+
+        CalcResult::Number(result)
+    }
+}

base/src/functions/statistical/mod.rs

@@ -1,12 +1,14 @@
 mod beta;
 mod binom;
 mod chisq;
+mod correl;
 mod count_and_average;
 mod covariance;
 mod devsq;
 mod exponential;
 mod fisher;
 mod gamma;
+mod gauss;
 mod geomean;
 mod hypegeom;
 mod if_ifs;
@@ -15,6 +17,7 @@ mod normal;
 mod pearson;
 mod phi;
 mod poisson;
+mod rank_eq_avg;
 mod standard_dev;
 mod standardize;
 mod t_dist;

base/src/functions/statistical/pearson.rs

@@ -1,5 +1,4 @@
 use crate::expressions::types::CellReferenceIndex;
-use crate::functions::statistical::chisq::is_same_shape_or_1d;
 use crate::{
     calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
 };
@@ -7,176 +6,9 @@ use crate::{
 impl Model {
     // PEARSON(array1, array2)
     pub(crate) fn fn_pearson(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
-        if args.len() != 2 {
-            return CalcResult::new_args_number_error(cell);
-        }
-
-        let left_arg = self.evaluate_node_in_context(&args[0], cell);
-        let right_arg = self.evaluate_node_in_context(&args[1], cell);
-
-        let (values_left, values_right) = match (left_arg, right_arg) {
-            (
-                CalcResult::Range {
-                    left: l1,
-                    right: r1,
-                },
-                CalcResult::Range {
-                    left: l2,
-                    right: r2,
-                },
-            ) => {
-                if l1.sheet != l2.sheet {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Ranges are in different sheets".to_string(),
-                    );
-                }
-
-                let rows1 = r1.row - l1.row + 1;
-                let cols1 = r1.column - l1.column + 1;
-                let rows2 = r2.row - l2.row + 1;
-                let cols2 = r2.column - l2.column + 1;
-
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Ranges must be of the same shape".to_string(),
-                    );
-                }
-
-                let values_left = match self.values_from_range(l1, r1) {
-                    Err(error) => return error,
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_range(l2, r2) {
-                    Err(error) => return error,
-                    Ok(v) => v,
-                };
-
-                (values_left, values_right)
-            }
-            (
-                CalcResult::Array(left),
-                CalcResult::Range {
-                    left: l2,
-                    right: r2,
-                },
-            ) => {
-                let rows2 = r2.row - l2.row + 1;
-                let cols2 = r2.column - l2.column + 1;
-
-                let rows1 = left.len() as i32;
-                let cols1 = if rows1 > 0 { left[0].len() as i32 } else { 0 };
-
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Array and range must be of the same shape".to_string(),
-                    );
-                }
-
-                let values_left = match self.values_from_array(left) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in first array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_range(l2, r2) {
-                    Err(error) => return error,
-                    Ok(v) => v,
-                };
-
-                (values_left, values_right)
-            }
-            (
-                CalcResult::Range {
-                    left: l1,
-                    right: r1,
-                },
-                CalcResult::Array(right),
-            ) => {
-                let rows1 = r1.row - l1.row + 1;
-                let cols1 = r1.column - l1.column + 1;
-
-                let rows2 = right.len() as i32;
-                let cols2 = if rows2 > 0 { right[0].len() as i32 } else { 0 };
-
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Range and array must be of the same shape".to_string(),
-                    );
-                }
-
-                let values_left = match self.values_from_range(l1, r1) {
-                    Err(error) => return error,
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_array(right) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in second array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-
-                (values_left, values_right)
-            }
-            (CalcResult::Array(left), CalcResult::Array(right)) => {
-                let rows1 = left.len() as i32;
-                let rows2 = right.len() as i32;
-                let cols1 = if rows1 > 0 { left[0].len() as i32 } else { 0 };
-                let cols2 = if rows2 > 0 { right[0].len() as i32 } else { 0 };
-
-                if !is_same_shape_or_1d(rows1, cols1, rows2, cols2) {
-                    return CalcResult::new_error(
-                        Error::VALUE,
-                        cell,
-                        "Arrays must be of the same shape".to_string(),
-                    );
-                }
-
-                let values_left = match self.values_from_array(left) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in first array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-                let values_right = match self.values_from_array(right) {
-                    Err(error) => {
-                        return CalcResult::new_error(
-                            Error::VALUE,
-                            cell,
-                            format!("Error in second array: {:?}", error),
-                        );
-                    }
-                    Ok(v) => v,
-                };
-
-                (values_left, values_right)
-            }
-            _ => {
-                return CalcResult::new_error(
-                    Error::VALUE,
-                    cell,
-                    "Both arguments must be ranges or arrays".to_string(),
-                );
-            }
+        let (_, _, values_left, values_right) = match self.fn_get_two_matrices(args, cell) {
+            Ok(result) => result,
+            Err(e) => return e,
         };
 
         // Flatten into (x, y) pairs, skipping non-numeric entries (None)
@@ -228,8 +60,54 @@ impl Model {
         }
 
         let denom = (denom_x * denom_y).sqrt();
-        let r = num / denom;
 
-        CalcResult::Number(r)
+        CalcResult::Number(num / denom)
+    }
+
+    // RSQ(array1, array2) = CORREL(array1, array2)^2
+    pub(crate) fn fn_rsq(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let (_rows, _cols, values1, values2) = match self.fn_get_two_matrices(args, cell) {
+            Ok(s) => s,
+            Err(e) => return e,
+        };
+
+        let mut n = 0.0_f64;
+        let mut sum_x = 0.0_f64;
+        let mut sum_y = 0.0_f64;
+        let mut sum_x2 = 0.0_f64;
+        let mut sum_y2 = 0.0_f64;
+        let mut sum_xy = 0.0_f64;
+
+        let len = values1.len().min(values2.len());
+        for i in 0..len {
+            if let (Some(x), Some(y)) = (values1[i], values2[i]) {
+                n += 1.0;
+                sum_x += x;
+                sum_y += y;
+                sum_x2 += x * x;
+                sum_y2 += y * y;
+                sum_xy += x * y;
+            }
+        }
+
+        if n < 2.0 {
+            return CalcResult::new_error(
+                Error::DIV,
+                cell,
+                "RSQ requires at least two numeric data points in each range".to_string(),
+            );
+        }
+
+        let num = n * sum_xy - sum_x * sum_y;
+        let denom_x = n * sum_x2 - sum_x * sum_x;
+        let denom_y = n * sum_y2 - sum_y * sum_y;
+        let denom = (denom_x * denom_y).sqrt();
+
+        if denom == 0.0 || !denom.is_finite() {
+            return CalcResult::new_error(Error::DIV, cell, "Division by zero in RSQ".to_string());
+        }
+
+        let r = num / denom;
+        CalcResult::Number(r * r)
     }
 }

base/src/functions/statistical/rank_eq_avg.rs

@@ -0,0 +1,202 @@
+use crate::expressions::types::CellReferenceIndex;
+use crate::{
+    calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
+};
+
+impl Model {
+    // Helper to collect numeric values from the 2nd argument of RANK.*
+    fn collect_rank_values(
+        &mut self,
+        arg: &Node,
+        cell: CellReferenceIndex,
+    ) -> Result<Vec<f64>, CalcResult> {
+        let values = match self.evaluate_node_in_context(arg, cell) {
+            CalcResult::Array(array) => match self.values_from_array(array) {
+                Ok(v) => v,
+                Err(e) => {
+                    return Err(CalcResult::Error {
+                        error: Error::VALUE,
+                        origin: cell,
+                        message: format!("Unsupported array argument: {}", e),
+                    })
+                }
+            },
+            CalcResult::Range { left, right } => self.values_from_range(left, right)?,
+            CalcResult::Boolean(value) => {
+                if !matches!(arg, Node::ReferenceKind { .. }) {
+                    vec![Some(if value { 1.0 } else { 0.0 })]
+                } else {
+                    return Err(CalcResult::Error {
+                        error: Error::NUM,
+                        origin: cell,
+                        message: "Unsupported argument type".to_string(),
+                    });
+                }
+            }
+            _ => {
+                return Err(CalcResult::Error {
+                    error: Error::NIMPL,
+                    origin: cell,
+                    message: "Unsupported argument type".to_string(),
+                })
+            }
+        };
+
+        let numeric_values: Vec<f64> = values.into_iter().flatten().collect();
+        Ok(numeric_values)
+    }
+
+    // RANK.EQ(number, ref, [order])
+    pub(crate) fn fn_rank_eq(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if !(2..=3).contains(&args.len()) {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        // number
+        let number = match self.get_number_no_bools(&args[0], cell) {
+            Ok(f) => f,
+            Err(e) => return e,
+        };
+
+        // ref
+        let mut values = match self.collect_rank_values(&args[1], cell) {
+            Ok(v) => v,
+            Err(e) => return e,
+        };
+
+        if values.is_empty() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "No numeric values for RANK.EQ".to_string(),
+            };
+        }
+
+        // order: default 0 (descending)
+        let order = if args.len() == 2 {
+            0.0
+        } else {
+            match self.get_number_no_bools(&args[2], cell) {
+                Ok(f) => f,
+                Err(e) => return e,
+            }
+        };
+
+        values.retain(|v| !v.is_nan());
+
+        // "better" = greater (descending) or smaller (ascending)
+        let mut better = 0;
+        let mut equal = 0;
+
+        if order == 0.0 {
+            // descending
+            for v in &values {
+                if *v > number {
+                    better += 1;
+                } else if *v == number {
+                    equal += 1;
+                }
+            }
+        } else {
+            // ascending
+            for v in &values {
+                if *v < number {
+                    better += 1;
+                } else if *v == number {
+                    equal += 1;
+                }
+            }
+        }
+
+        if equal == 0 {
+            return CalcResult::Error {
+                error: Error::NA,
+                origin: cell,
+                message: "Number not found in reference for RANK.EQ".to_string(),
+            };
+        }
+
+        let rank = (better as f64) + 1.0;
+        CalcResult::Number(rank)
+    }
+
+    // RANK.AVG(number, ref, [order])
+    pub(crate) fn fn_rank_avg(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if !(2..=3).contains(&args.len()) {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        // number
+        let number = match self.get_number_no_bools(&args[0], cell) {
+            Ok(f) => f,
+            Err(e) => return e,
+        };
+
+        // ref
+        let mut values = match self.collect_rank_values(&args[1], cell) {
+            Ok(v) => v,
+            Err(e) => return e,
+        };
+
+        if values.is_empty() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "No numeric values for RANK.AVG".to_string(),
+            };
+        }
+
+        // order: default 0 (descending)
+        let order = if args.len() == 2 {
+            0.0
+        } else {
+            match self.get_number_no_bools(&args[2], cell) {
+                Ok(f) => f,
+                Err(e) => return e,
+            }
+        };
+
+        values.retain(|v| !v.is_nan());
+
+        // > or < depending on order
+        let mut better = 0;
+        let mut equal = 0;
+
+        if order == 0.0 {
+            // descending
+            for v in &values {
+                if *v > number {
+                    better += 1;
+                } else if *v == number {
+                    equal += 1;
+                }
+            }
+        } else {
+            // ascending
+            for v in &values {
+                if *v < number {
+                    better += 1;
+                } else if *v == number {
+                    equal += 1;
+                }
+            }
+        }
+
+        if equal == 0 {
+            return CalcResult::Error {
+                error: Error::NA,
+                origin: cell,
+                message: "Number not found in reference for RANK.AVG".to_string(),
+            };
+        }
+
+        // For ties, average of the ranks. If the equal values occupy positions
+        // (better+1) ..= (better+equal), the average is:
+        // better + (equal + 1) / 2
+        let better_f = better as f64;
+        let equal_f = equal as f64;
+        let rank = better_f + (equal_f + 1.0) / 2.0;
+
+        CalcResult::Number(rank)
+    }
+}

base/src/functions/statistical/t_dist.rs

@@ -17,7 +17,7 @@ fn mean(xs: &[f64]) -> f64 {
     s / (n as f64)
 }
 
-fn sample_var(xs: &[f64]) -> f64 {
+pub(crate) fn sample_var(xs: &[f64]) -> f64 {
     let n = xs.len();
     if n < 2 {
         return 0.0;

base/src/test/mod.rs

@@ -18,7 +18,6 @@ mod test_fn_concatenate;
 mod test_fn_count;
 mod test_fn_day;
 mod test_fn_exact;
-mod test_fn_fact;
 mod test_fn_financial;
 mod test_fn_formulatext;
 mod test_fn_if;
@@ -46,6 +45,7 @@ mod test_set_user_input;
 mod test_sheet_markup;
 mod test_sheets;
 mod test_styles;
+mod test_sumsq;
 mod test_trigonometric;
 mod test_true_false;
 mod test_weekday_return_types;
@@ -66,6 +66,7 @@ mod test_escape_quotes;
 mod test_even_odd;
 mod test_exp_sign;
 mod test_extend;
+mod test_floor;
 mod test_fn_datevalue_timevalue;
 mod test_fn_fv;
 mod test_fn_round;

base/src/test/statistical/mod.rs

@@ -7,7 +7,9 @@ mod test_fn_covariance;
 mod test_fn_devsq;
 mod test_fn_expon_dist;
 mod test_fn_f;
+mod test_fn_f_test;
 mod test_fn_fisher;
+mod test_fn_gauss;
 mod test_fn_hyp_geom_dist;
 mod test_fn_log_norm;
 mod test_fn_norm_dist;

base/src/test/statistical/test_fn_f_test.rs

@@ -0,0 +1,35 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+
+#[test]
+fn test_fn_f_test_sanity() {
+    let mut model = new_empty_model();
+
+    // Valid call
+    model._set("A1", "=F.TEST(A2:A7, B2:B7)");
+    model._set("A2", "9");
+    model._set("A3", "12");
+    model._set("A4", "14");
+    model._set("A5", "16");
+    model._set("A6", "18");
+    model._set("A7", "20");
+    model._set("B2", "11");
+    model._set("B3", "10");
+    model._set("B4", "15");
+    model._set("B5", "17");
+    model._set("B6", "19");
+    model._set("B7", "21");
+
+    // Too few args
+    model._set("A8", "=F.TEST(A2:A7)");
+
+    // Too many args
+    model._set("A9", "=F.TEST(A2:A7, B2:B7, C2:C7)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"0.859284302");
+    assert_eq!(model._get_text("A8"), *"#ERROR!");
+    assert_eq!(model._get_text("A9"), *"#ERROR!");
+}

base/src/test/statistical/test_fn_gauss.rs

@@ -0,0 +1,35 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+
+#[test]
+fn test_fn_gauss_smoke() {
+    let mut model = new_empty_model();
+    model._set("A1", "=GAUSS(-3)");
+    model._set("A2", "=GAUSS(-2.3)");
+    model._set("A3", "=GAUSS(-1.7)");
+    model._set("A4", "=GAUSS(0)");
+    model._set("A5", "=GAUSS(0.5)");
+    model._set("A6", "=GAUSS(1)");
+    model._set("A7", "=GAUSS(1.3)");
+    model._set("A8", "=GAUSS(3)");
+    model._set("A9", "=GAUSS(4)");
+
+    model._set("G6", "=GAUSS()");
+    model._set("G7", "=GAUSS(1, 1)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"-0.498650102");
+    assert_eq!(model._get_text("A2"), *"-0.48927589");
+    assert_eq!(model._get_text("A3"), *"-0.455434537");
+    assert_eq!(model._get_text("A4"), *"0");
+    assert_eq!(model._get_text("A5"), *"0.191462461");
+    assert_eq!(model._get_text("A6"), *"0.341344746");
+    assert_eq!(model._get_text("A7"), *"0.403199515");
+    assert_eq!(model._get_text("A8"), *"0.498650102");
+    assert_eq!(model._get_text("A9"), *"0.499968329");
+
+    assert_eq!(model._get_text("G6"), *"#ERROR!");
+    assert_eq!(model._get_text("G7"), *"#ERROR!");
+}

base/src/test/test_cell_info_n_sheets

@@ -0,0 +1,35 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+
+#[test]
+fn arguments() {
+    let mut model = new_empty_model();
+    model._set("A1", "=CELL("address",A1)");
+    model._set("A2", "=CELL()");
+
+    model._set("A3", "=INFO("system")");
+    model._set("A4", "=INFO()");
+
+    model._set("A5", "=N(TRUE)");
+    model._set("A6", "=N()");
+    model._set("A7", "=N(1, 2)");
+
+    model._set("A8", "=SHEETS()");
+    model._set("A9", "=SHEETS(1)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"$A$1");
+    assert_eq!(model._get_text("A2"), *"#ERROR!");
+
+    assert_eq!(model._get_text("A3"), *"#N/IMPL!");
+    assert_eq!(model._get_text("A4"), *"#ERROR!");
+
+    assert_eq!(model._get_text("A5"), *"1");
+    assert_eq!(model._get_text("A6"), *"#ERROR!");
+    assert_eq!(model._get_text("A7"), *"#ERROR!");
+
+    assert_eq!(model._get_text("A8"), *"1");
+    assert_eq!(model._get_text("A9"), *"#N/IMPL!");
+}

base/src/test/test_floor.rs

@@ -0,0 +1,123 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+
+#[test]
+fn test_floor_floating_point_precision() {
+    // This test specifically checks the floating-point precision bug fix
+    // Bug: FLOOR(7.1, 0.1) was returning 7.0 instead of 7.1
+    let mut model = new_empty_model();
+
+    // FLOOR tests
+    model._set("C5", "=FLOOR(7.1, 0.1)");
+    model._set("H7", "=FLOOR(-7.1, -0.1)");
+
+    // FLOOR.PRECISE tests
+    model._set("C53", "=FLOOR.PRECISE(7.1, 0.1)");
+    model._set("H53", "=FLOOR.PRECISE(7.1, -0.1)");
+
+    // FLOOR.MATH tests
+    model._set("C101", "=FLOOR.MATH(7.1, 0.1)");
+    model._set("H101", "=FLOOR.MATH(7.1, -0.1)");
+
+    model.evaluate();
+
+    // All should return 7.1
+    assert_eq!(model._get_text("C5"), *"7.1");
+    assert_eq!(model._get_text("H7"), *"-7.1");
+    assert_eq!(model._get_text("C53"), *"7.1");
+    assert_eq!(model._get_text("H53"), *"7.1");
+    assert_eq!(model._get_text("C101"), *"7.1");
+    assert_eq!(model._get_text("H101"), *"7.1");
+}
+
+#[test]
+fn test_floor_additional_precision_cases() {
+    let mut model = new_empty_model();
+    model._set("A1", "=FLOOR(7.9, 0.1)");
+    model._set("A2", "=FLOOR(2.6, 0.5)");
+    model._set("A3", "=FLOOR(0.3, 0.1)"); // 0.1 + 0.2 type scenario
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"7.9");
+    assert_eq!(model._get_text("A2"), *"2.5");
+    assert_eq!(model._get_text("A3"), *"0.3");
+}
+
+#[test]
+fn test_floor_basic_cases() {
+    let mut model = new_empty_model();
+    model._set("A1", "=FLOOR(3.7, 2)");
+    model._set("A2", "=FLOOR(3.2, 1)");
+    model._set("A3", "=FLOOR(10, 3)");
+    model._set("A4", "=FLOOR(7, 2)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"2");
+    assert_eq!(model._get_text("A2"), *"3");
+    assert_eq!(model._get_text("A3"), *"9");
+    assert_eq!(model._get_text("A4"), *"6");
+}
+
+#[test]
+fn test_floor_negative_numbers() {
+    let mut model = new_empty_model();
+    // Both negative: rounds toward zero
+    model._set("A1", "=FLOOR(-2.5, -2)");
+    model._set("A2", "=FLOOR(-11, -3)");
+
+    // Negative number, positive significance: rounds away from zero
+    model._set("A3", "=FLOOR(-11, 3)");
+    model._set("A4", "=FLOOR(-2.5, 2)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"-2");
+    assert_eq!(model._get_text("A2"), *"-9");
+    assert_eq!(model._get_text("A3"), *"-12");
+    assert_eq!(model._get_text("A4"), *"-4");
+}
+
+#[test]
+fn test_floor_error_cases() {
+    let mut model = new_empty_model();
+    // Positive number with negative significance should error
+    model._set("A1", "=FLOOR(2.5, -2)");
+    model._set("A2", "=FLOOR(10, -3)");
+
+    // Division by zero
+    model._set("A3", "=FLOOR(5, 0)");
+
+    // Wrong number of arguments
+    model._set("A4", "=FLOOR(5)");
+    model._set("A5", "=FLOOR(5, 1, 1)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"#NUM!");
+    assert_eq!(model._get_text("A2"), *"#NUM!");
+    assert_eq!(model._get_text("A3"), *"#DIV/0!");
+    assert_eq!(model._get_text("A4"), *"#ERROR!");
+    assert_eq!(model._get_text("A5"), *"#ERROR!");
+}
+
+#[test]
+fn test_floor_edge_cases() {
+    let mut model = new_empty_model();
+    // Zero value
+    model._set("A1", "=FLOOR(0, 5)");
+    model._set("A2", "=FLOOR(0, 0)");
+
+    // Exact multiples
+    model._set("A3", "=FLOOR(10, 5)");
+    model._set("A4", "=FLOOR(9, 3)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"0");
+    assert_eq!(model._get_text("A2"), *"0");
+    assert_eq!(model._get_text("A3"), *"10");
+    assert_eq!(model._get_text("A4"), *"9");
+}

base/src/test/test_fn_fact.rs

@@ -1,29 +0,0 @@
-#![allow(clippy::unwrap_used)]
-
-use crate::test::util::new_empty_model;
-
-#[test]
-fn large_numbers() {
-    let mut model = new_empty_model();
-    model._set("A1", "=FACT(170)");
-    model._set("A2", "=FACTDOUBLE(36)");
-
-    model._set("B1", "=FACT(6)");
-    model._set("B2", "=FACTDOUBLE(6)");
-
-    model._set("C3", "=FACTDOUBLE(15)");
-
-    model._set("F3", "=FACT(-0.1)");
-    model._set("F4", "=FACT(0)");
-
-    model.evaluate();
-
-    assert_eq!(model._get_text("A1"), *"7.25742E+306");
-    assert_eq!(model._get_text("A2"), *"1.67834E+21");
-    assert_eq!(model._get_text("B1"), *"720");
-    assert_eq!(model._get_text("B2"), *"48");
-    assert_eq!(model._get_text("C3"), *"2027025");
-
-    assert_eq!(model._get_text("F3"), *"#NUM!");
-    assert_eq!(model._get_text("F4"), *"1");
-}

base/src/test/test_now.rs

@@ -7,15 +7,24 @@ const TIMESTAMP_2023: i64 = 1679319865208;
 
 #[test]
 fn arguments() {
+    mock_time::set_mock_time(TIMESTAMP_2023);
     let mut model = new_empty_model();
 
-    model._set("A1", "=NOW(1)");
+    model._set("A1", "=NOW(1, 1)");
+    model._set("A2", "=NOW(\"Europe/Berlin\")");
+    model._set("A3", "=NOW(\"faketimezone\")");
     model.evaluate();
 
     assert_eq!(
         model._get_text("A1"),
         "#ERROR!",
-        "NOW should not accept arguments"
+        "Wrong number of arguments"
+    );
+    assert_eq!(model._get_text("A2"), *"20/03/2023 14:44:25");
+    assert_eq!(
+        model._get_text("A3"),
+        "#VALUE!",
+        "Invalid timezone: faketimezone"
     );
 }
 

base/src/test/test_sumsq.rs

@@ -0,0 +1,17 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+
+#[test]
+fn arguments() {
+    let mut model = new_empty_model();
+    model._set("A1", "=SUMSQ()");
+    model._set("A2", "=SUMSQ(2)");
+    model._set("A3", "=SUMSQ(1, 2)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"#ERROR!");
+    assert_eq!(model._get_text("A2"), *"4");
+    assert_eq!(model._get_text("A3"), *"5");
+}

docs/src/functions/information.md

@@ -11,7 +11,7 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 
 | Function   | Status                                         | Documentation |
 | ---------- | ---------------------------------------------- | ------------- |
-| CELL       | <Badge type="info" text="Not implemented yet" /> | –             |
+| CELL       | <Badge type="tip" text="Available" />          | –             |
 | ERROR.TYPE | <Badge type="tip" text="Available" />          | –             |
 | INFO       | <Badge type="info" text="Not implemented yet" /> | –             |
 | ISBLANK    | <Badge type="tip" text="Available" />          | –             |
@@ -20,7 +20,7 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 | ISEVEN     | <Badge type="tip" text="Available" />          | –             |
 | ISFORMULA  | <Badge type="tip" text="Available" />          | –             |
 | ISLOGICAL  | <Badge type="tip" text="Available" />          | –             |
-| ISNA       | <Badge type="info" text="Not implemented yet" /> | –             |
+| ISNA       | <Badge type="tip" text="Available" />          | –             |
 | ISNONTEXT  | <Badge type="tip" text="Available" />          | –             |
 | ISNUMBER   | <Badge type="tip" text="Available" />          | –             |
 | ISODD      | <Badge type="tip" text="Available" />          | –             |
@@ -30,5 +30,5 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 | N          | <Badge type="info" text="Not implemented yet" /> | –             |
 | NA         | <Badge type="tip" text="Available" />          | –             |
 | SHEET      | <Badge type="tip" text="Available" />          | –             |
-| SHEETS     | <Badge type="info" text="Not implemented yet" /> | –             |
+| SHEETS     | <Badge type="tip" text="Available" />          | –             |
 | TYPE       | <Badge type="tip" text="Available" />          | –             |

docs/src/functions/information/cell.md

@@ -7,6 +7,5 @@ lang: en-US
 # CELL
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
+🚧 This function is implemented but currently lacks detailed documentation. For guidance, you may refer to the equivalent functionality in [Microsoft Excel documentation](https://support.microsoft.com/en-us/office/excel-functions-by-category-5f91f4e9-7b42-46d2-9bd1-63f26a86c0eb).
 :::

docs/src/functions/information/n.md

@@ -7,6 +7,5 @@ lang: en-US
 # N
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
+🚧 This function is implemented but currently lacks detailed documentation. For guidance, you may refer to the equivalent functionality in [Microsoft Excel documentation](https://support.microsoft.com/en-us/office/excel-functions-by-category-5f91f4e9-7b42-46d2-9bd1-63f26a86c0eb).
 :::

docs/src/functions/information/sheets.md

@@ -7,6 +7,5 @@ lang: en-US
 # SHEETS
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
+🚧 This function is implemented but currently lacks detailed documentation. For guidance, you may refer to the equivalent functionality in [Microsoft Excel documentation](https://support.microsoft.com/en-us/office/excel-functions-by-category-5f91f4e9-7b42-46d2-9bd1-63f26a86c0eb).
 :::

docs/src/functions/lookup_and_reference/column.md

@@ -6,26 +6,33 @@ lang: en-US
 
 # COLUMN function
 ## Overview
-The COLUMN Function in IronCalc is a lookup & reference formula that is used to query and return the column number of a referenced Column or Cell.
+The COLUMN Function in IronCalc is a lookup & reference formula that is used to query and return the column number of a referenced column or cell.
 ## Usage
 ### Syntax
 **COLUMN(<span title="Reference" style="color:#1E88E5">reference</span>) => <span title="Number" style="color:#1E88E5">column</span>**
 ### Argument descriptions
-* *reference* ([cell](/features/value-types#references), [optional](/features/optional-arguments.md)). The number of the cell you wish to reference the column number of.
+* *reference* ([cell](/features/value-types#references), [optional](/features/optional-arguments.md)). The cell, column, range, or [Named Range](/web-application/name-manager.html) for which you wish to find the column number.
 ### Additional guidance
-* When referencing a range of cells, only the column number of the left most cell will be returned.
+* When referencing a range of cells, only the column number of the leftmost cell will be returned.
 * You are also able to reference complete columns instead of individual cells.
+* When using a Named Range as a reference, the reference is not case sensitive.
+* IronCalc supports the use of both *Absolute* ($A$1) and *Relative* (A1) references.
+* Cross-sheet references are also supported.
 ### Returned value
-COLUMN returns the [number](/features/value-types#numbers) of the specific cell or column which is being referenced.
+COLUMN returns the [number](/features/value-types#numbers) of the specific cell or column which is being referenced. If no reference is included, the column number of the cell where the formula is entered will be returned.
 ### Error conditions
-* IronCalc currently does not support the referencing of cells with names.
+* A [#NAME?](/features/error-types.html#name) error is returned if a Named Range being referenced is deleted.
+* A [#REF!](/features/error-types.html#ref) error is returned if a cell being referenced is deleted.
+* A [#VALUE!](/features/error-types.html#value) error is returned if a column being referenced is deleted.
 ## Details
-The COLUMN Function can only be used to display the correlating number of a single column within a Sheet. If you wish to show the number of columns used within a specific range, you can use the COLUMNS Function.
+The COLUMN Function can only be used to display the correlating number of a single column within a Sheet. If you wish to show the number of columns used within a specific range, you can use the [COLUMNS](/functions/lookup_and_reference/columns) Function.
 ## Examples
 ### No Cell Reference
-When no cell reference is made, the formula uses **=COLUMN()**. This will then output the column number of the cell where the formula is placed.<br><br>For example, if the formula is placed in cell A1, then "1" will be displayed.
+When no cell reference is made, the formula uses **=COLUMN()**. This will output the column number of the cell where the formula is entered.<br><br>For example, if the formula is placed in cell A1, then "1" will be displayed.
 ### With Cell Reference
-When a cell reference is made, the formula uses **=COLUMN([Referenced Cell])**. This will then output the column number of the referenced cell, regardless of where the formula is placed in the sheet.<br><br>For example, if the cell B1 is the referenced cell, "2" will be the output of the formula no matter where it is placed in the sheet.<br><br>**Note:** references do not always have to be specific cells, you can also reference complete columns. For example, **=COLUMN(B:B)** would also result in an output of "2".
+When a cell reference is made, the formula uses **=COLUMN(<span title="Reference" style="color:#1E88E5">Referenced Cell</span>)**. This will then output the column number of the referenced cell, regardless of where the formula is placed in the sheet.<br><br>For example, if B1 is the referenced cell, then "2" will be the output of the formula, regardless of where the formula is placed in the sheet.<br><br>**Note:** references do not have to be specific cells, you can also reference complete columns. For example, **=COLUMN(B:B)** would also result in an output of "2".
 ### Range References
-The COLUMN function can also be used to reference a range of Cells or Columns. In this case only the most left-hand column will be the resulting output.<br><br>For example, **=COLUMN(A1:J1)** will result in the ouput of "1".
-## Links
+The COLUMN function can also be used to reference a range of cells or columns. In this case only the leftmost column will be the resulting output.<br><br>For example, **=COLUMN(A1:J1)** will result in the output of "1".
+## Links
+* Visit Microsoft Excel's [Column function](https://support.microsoft.com/en-us/office/column-function-44e8c754-711c-4df3-9da4-47a55042554b) page.
+* Both [Google Sheets](https://support.google.com/docs/answer/3093373) and [LibreOffice Calc](https://wiki.documentfoundation.org/Documentation/Calc_Functions/COLUMN) provide versions of the COLUMN function.

docs/src/functions/math-and-trigonometry.md

@@ -86,7 +86,7 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 | SUMIF           | <Badge type="tip" text="Available" />          | –             |
 | SUMIFS          | <Badge type="tip" text="Available" />         | –             |
 | SUMPRODUCT      | <Badge type="info" text="Not implemented yet" /> | –             |
-| SUMSQ           | <Badge type="info" text="Not implemented yet" /> | –             |
+| SUMSQ           | <Badge type="tip" text="Available" />          | –             |
 | SUMX2MY2        | <Badge type="info" text="Not implemented yet" /> | –             |
 | SUMX2PY2        | <Badge type="info" text="Not implemented yet" /> | –             |
 | SUMXMY2         | <Badge type="info" text="Not implemented yet" /> | –             |

docs/src/functions/math_and_trigonometry/sumsq.md

@@ -7,6 +7,5 @@ lang: en-US
 # SUMSQ
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
+🚧 This function is implemented but currently lacks detailed documentation. For guidance, you may refer to the equivalent functionality in [Microsoft Excel documentation](https://support.microsoft.com/en-us/office/excel-functions-by-category-5f91f4e9-7b42-46d2-9bd1-63f26a86c0eb).
 :::

webapp/IronCalc/src/components/Editor/util.tsx

@@ -194,6 +194,10 @@ function getFormulaHTML(
   } else {
     html = [<span key="single">{text}</span>];
   }
+  // Add a trailing character if text ends with newline to ensure selector's height grows
+  if (text.endsWith("\n")) {
+    html.push(<span key="trailing-newline">{"\n"}</span>);
+  }
   return { html, activeRanges };
 }
 

webapp/IronCalc/src/components/Worksheet/Worksheet.tsx

@@ -17,6 +17,7 @@ import {
   LAST_ROW,
   outlineBackgroundColor,
   outlineColor,
+  outlineEditingColor,
   ROW_HEIGH_SCALE,
 } from "../WorksheetCanvas/constants";
 import WorksheetCanvas from "../WorksheetCanvas/worksheetCanvas";
@@ -226,12 +227,14 @@ const Worksheet = forwardRef(
         if (!canvas) {
           return;
         }
+        workbookState.setSelecting(true);
         const { row, column } = cell;
         model.onAreaSelecting(row, column);
         canvas.renderSheet();
         refresh();
       },
       onAreaSelected: () => {
+        workbookState.setSelecting(false);
         const styles = workbookState.getCopyStyles();
         if (styles?.length) {
           model.onPasteStyles(styles);
@@ -505,8 +508,8 @@ const RowResizeGuide = styled("div")`
 
 const AreaOutline = styled("div")`
   position: absolute;
-  border: 1px solid ${outlineColor};
-  border-radius: 3px;
+  border: 0px solid ${outlineColor};
+  border-radius: 1px;
   background-color: ${outlineBackgroundColor};
 `;
 
@@ -517,6 +520,7 @@ const CellOutline = styled("div")`
   word-break: break-word;
   font-size: 13px;
   display: flex;
+  box-shadow: inset 0 0 0 1px white;
 `;
 
 const ExtendToOutline = styled("div")`
@@ -536,6 +540,8 @@ const EditorWrapper = styled("div")`
   vertical-align: bottom;
   overflow: hidden;
   text-align: left;
+  outline: 3px solid ${outlineEditingColor};
+  z-index: 1000;
   span {
     min-width: 1px;
   }

webapp/IronCalc/src/components/WorksheetCanvas/constants.ts

@@ -12,6 +12,7 @@ export const gridSeparatorColor = "#E0E0E0";
 export const defaultTextColor = "#2E414D";
 
 export const outlineColor = "#F2994A";
+export const outlineEditingColor = "#FBE0C9";
 export const outlineBackgroundColor = "#F2994A1A";
 
 export const LAST_COLUMN = 16_384;

webapp/IronCalc/src/components/WorksheetCanvas/outlineHandle.ts

@@ -26,6 +26,7 @@ export function attachOutlineHandle(
     background: outlineColor,
     cursor: "crosshair",
     borderRadius: "1px",
+    border: `1px solid white`,
   });
 
   // cell handle events

webapp/IronCalc/src/components/WorksheetCanvas/worksheetCanvas.ts

@@ -1,5 +1,6 @@
 import type { CellStyle, Model } from "@ironcalc/wasm";
 import { columnNameFromNumber } from "@ironcalc/wasm";
+import { theme } from "../../theme";
 import { getColor } from "../Editor/util";
 import type { Cell } from "../types";
 import type { WorkbookState } from "../workbookState";
@@ -721,7 +722,7 @@ export default class WorksheetCanvas {
     const style = this.model.getCellStyle(selectedSheet, row, column);
 
     // first the background
-    let backgroundColor = "#FFFFFF";
+    let backgroundColor = theme.palette.common.white;
     if (style.fill.fg_color) {
       backgroundColor = style.fill.fg_color;
     }
@@ -1036,14 +1037,21 @@ export default class WorksheetCanvas {
     width: number,
     div: HTMLDivElement,
     selected: boolean,
+    isFullColumnSelected: boolean,
   ): void {
     div.style.boxSizing = "border-box";
     div.style.width = `${width}px`;
     div.style.height = `${headerRowHeight}px`;
     div.style.backgroundColor = selected
-      ? headerSelectedBackground
+      ? isFullColumnSelected
+        ? theme.palette.primary.main
+        : headerSelectedBackground
       : headerBackground;
-    div.style.color = selected ? headerSelectedColor : headerTextColor;
+    div.style.color = selected
+      ? isFullColumnSelected
+        ? theme.palette.common.white
+        : headerSelectedColor
+      : headerTextColor;
     div.style.fontWeight = "bold";
     div.style.borderLeft = `1px solid ${headerBorderColor}`;
     div.style.borderTop = `1px solid ${headerBorderColor}`;
@@ -1071,9 +1079,15 @@ export default class WorksheetCanvas {
     const { sheet: selectedSheet, range } = this.model.getSelectedView();
     let rowStart = range[0];
     let rowEnd = range[2];
+    let columnStart = range[1];
+    let columnEnd = range[3];
     if (rowStart > rowEnd) {
       [rowStart, rowEnd] = [rowEnd, rowStart];
     }
+    if (columnStart > columnEnd) {
+      [columnStart, columnEnd] = [columnEnd, columnStart];
+    }
+    const isFullRowSelected = columnStart === 1 && columnEnd === LAST_COLUMN;
     const context = this.ctx;
 
     let topLeftCornerY = headerRowHeight + 0.5;
@@ -1085,7 +1099,9 @@ export default class WorksheetCanvas {
       context.fillStyle = headerBorderColor;
       context.fillRect(0.5, topLeftCornerY, headerColumnWidth, rowHeight);
       context.fillStyle = selected
-        ? headerSelectedBackground
+        ? isFullRowSelected
+          ? theme.palette.primary.main
+          : headerSelectedBackground
         : headerBackground;
       context.fillRect(
         0.5,
@@ -1097,7 +1113,11 @@ export default class WorksheetCanvas {
         context.fillStyle = outlineColor;
         context.fillRect(headerColumnWidth - 1, topLeftCornerY, 1, rowHeight);
       }
-      context.fillStyle = selected ? headerSelectedColor : headerTextColor;
+      context.fillStyle = selected
+        ? isFullRowSelected
+          ? theme.palette.common.white
+          : headerSelectedColor
+        : headerTextColor;
       context.font = `bold 12px ${defaultCellFontFamily}`;
       context.fillText(
         `${row}`,
@@ -1122,11 +1142,17 @@ export default class WorksheetCanvas {
     const { columnHeaders } = this;
     let deltaX = 0;
     const { range } = this.model.getSelectedView();
+    let rowStart = range[0];
+    let rowEnd = range[2];
     let columnStart = range[1];
     let columnEnd = range[3];
     if (columnStart > columnEnd) {
       [columnStart, columnEnd] = [columnEnd, columnStart];
     }
+    if (rowStart > rowEnd) {
+      [rowStart, rowEnd] = [rowEnd, rowStart];
+    }
+    const isFullColumnSelected = rowStart === 1 && rowEnd === LAST_ROW;
     for (const header of columnHeaders.querySelectorAll(".column-header"))
       header.remove();
     for (const handle of columnHeaders.querySelectorAll(
@@ -1146,7 +1172,12 @@ export default class WorksheetCanvas {
     // Frozen headers
     for (let column = 1; column <= frozenColumns; column += 1) {
       const selected = column >= columnStart && column <= columnEnd;
-      deltaX += this.addColumnHeader(deltaX, column, selected);
+      deltaX += this.addColumnHeader(
+        deltaX,
+        column,
+        selected,
+        isFullColumnSelected,
+      );
     }
 
     if (frozenColumns !== 0) {
@@ -1162,7 +1193,12 @@ export default class WorksheetCanvas {
 
     for (let column = firstColumn; column <= lastColumn; column += 1) {
       const selected = column >= columnStart && column <= columnEnd;
-      deltaX += this.addColumnHeader(deltaX, column, selected);
+      deltaX += this.addColumnHeader(
+        deltaX,
+        column,
+        selected,
+        isFullColumnSelected,
+      );
     }
 
     columnHeaders.style.width = `${deltaX}px`;
@@ -1172,6 +1208,7 @@ export default class WorksheetCanvas {
     deltaX: number,
     column: number,
     selected: boolean,
+    isFullColumnSelected: boolean,
   ): number {
     const columnWidth = this.getColumnWidth(
       this.model.getSelectedSheet(),
@@ -1182,7 +1219,7 @@ export default class WorksheetCanvas {
     div.textContent = columnNameFromNumber(column);
     this.columnHeaders.insertBefore(div, null);
 
-    this.styleColumnHeader(columnWidth, div, selected);
+    this.styleColumnHeader(columnWidth, div, selected, isFullColumnSelected);
     this.addColumnResizeHandle(deltaX + columnWidth, column, columnWidth);
     return columnWidth;
   }
@@ -1523,7 +1560,9 @@ export default class WorksheetCanvas {
       return;
     }
     cellOutline.style.visibility = "visible";
-    cellOutlineHandle.style.visibility = "visible";
+    cellOutlineHandle.style.visibility = this.workbookState.isSelecting()
+      ? "hidden"
+      : "visible";
     areaOutline.style.visibility = "visible";
 
     const [selectedSheet, selectedRow, selectedColumn] =
@@ -1582,7 +1621,9 @@ export default class WorksheetCanvas {
       handleY += this.getRowHeight(selectedSheet, rowStart);
     } else {
       areaOutline.style.visibility = "visible";
-      cellOutlineHandle.style.visibility = "visible";
+      cellOutlineHandle.style.visibility = this.workbookState.isSelecting()
+        ? "hidden"
+        : "visible";
       const [areaX, areaY] = this.getCoordinatesByCell(rowStart, columnStart);
       const [areaWidth, areaHeight] = this.getAreaDimensions(
         rowStart,
@@ -1592,10 +1633,13 @@ export default class WorksheetCanvas {
       );
       handleX = areaX + areaWidth;
       handleY = areaY + areaHeight;
+      const isSelecting = this.workbookState.isSelecting();
+      // Add 1px when selecting to compensate for missing border
+      const borderCompensation = isSelecting ? 1 : 0;
       areaOutline.style.left = `${areaX - padding - 1}px`;
       areaOutline.style.top = `${areaY - padding - 1}px`;
-      areaOutline.style.width = `${areaWidth + 2 * padding + 1}px`;
-      areaOutline.style.height = `${areaHeight + 2 * padding + 1}px`;
+      areaOutline.style.width = `${areaWidth + 2 * padding + 1 + borderCompensation}px`;
+      areaOutline.style.height = `${areaHeight + 2 * padding + 1 + borderCompensation}px`;
       const clipLeft = rowStart < topLeftCell.row && rowStart > frozenRows;
       const clipTop =
         columnStart < topLeftCell.column && columnStart > frozenColumns;
@@ -1607,7 +1651,9 @@ export default class WorksheetCanvas {
         clipLeft,
         clipTop,
       );
-      areaOutline.style.border = `1px solid ${outlineColor}`;
+      areaOutline.style.border = isSelecting
+        ? "none"
+        : `1px solid ${outlineColor}`;
       // hide the handle if it is out of the visible area
       if (
         (rowEnd > frozenRows && rowEnd < topLeftCell.row - 1) ||

webapp/IronCalc/src/components/workbookState.ts

@@ -92,6 +92,7 @@ export class WorkbookState {
   private copyStyles: AreaStyles | null;
   private cell: EditingCell | null;
   private cutRange: CutRange | null;
+  private selecting: boolean;
 
   constructor() {
     // the extendTo area is the area we are covering
@@ -99,6 +100,15 @@ export class WorkbookState {
     this.copyStyles = null;
     this.cell = null;
     this.cutRange = null;
+    this.selecting = false;
+  }
+
+  isSelecting(): boolean {
+    return this.selecting;
+  }
+
+  setSelecting(value: boolean): void {
+    this.selecting = value;
   }
 
   getExtendToArea(): Area | null {

webapp/app.ironcalc.com/frontend/package-lock.json

@@ -91,6 +91,7 @@
       "integrity": "sha512-e7jT4DxYvIDLk1ZHmU/m/mB19rex9sv0c2ftBtjSBv+kVM/902eh0fINUzD7UwLLNR+jU585GxUJ8/EBfAM5fw==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "@babel/code-frame": "^7.27.1",
         "@babel/generator": "^7.28.5",
@@ -570,6 +571,7 @@
       "resolved": "https://registry.npmjs.org/@emotion/react/-/react-11.14.0.tgz",
       "integrity": "sha512-O000MLDBDdk/EohJPFUqvnp4qnHeYkVP5B0xEG0D/L7cOKP9kefu2DXn8dj74cQfsEzUqh+sr1RzFqiL1o+PpA==",
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "@babel/runtime": "^7.18.3",
         "@emotion/babel-plugin": "^11.13.5",
@@ -613,6 +615,7 @@
       "resolved": "https://registry.npmjs.org/@emotion/styled/-/styled-11.14.1.tgz",
       "integrity": "sha512-qEEJt42DuToa3gurlH4Qqc1kVpNq8wO8cJtDzU46TjlzWjDlsVyevtYCRijVq3SrHsROS+gVQ8Fnea108GnKzw==",
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "@babel/runtime": "^7.18.3",
         "@emotion/babel-plugin": "^11.13.5",
@@ -2026,6 +2029,7 @@
       "resolved": "https://registry.npmjs.org/@types/react/-/react-19.2.4.tgz",
       "integrity": "sha512-tBFxBp9Nfyy5rsmefN+WXc1JeW/j2BpBHFdLZbEVfs9wn3E3NRFxwV0pJg8M1qQAexFpvz73hJXFofV0ZAu92A==",
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "csstype": "^3.0.2"
       }
@@ -2122,6 +2126,7 @@
         }
       ],
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "baseline-browser-mapping": "^2.8.25",
         "caniuse-lite": "^1.0.30001754",
@@ -2691,6 +2696,7 @@
       "integrity": "sha512-5gTmgEY/sqK6gFXLIsQNH19lWb4ebPDLA4SdLP7dsWkIXHWlG66oPuVvXSGFPppYZz8ZDZq0dYYrbHfBCVUb1Q==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "engines": {
         "node": ">=12"
       },
@@ -2758,6 +2764,7 @@
       "resolved": "https://registry.npmjs.org/react/-/react-19.2.0.tgz",
       "integrity": "sha512-tmbWg6W31tQLeB5cdIBOicJDJRR2KzXsV7uSK9iNfLWQ5bIZfxuPEHp7M8wiHyHnn0DD1i7w3Zmin0FtkrwoCQ==",
       "license": "MIT",
+      "peer": true,
       "engines": {
         "node": ">=0.10.0"
       }
@@ -2767,6 +2774,7 @@
       "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-19.2.0.tgz",
       "integrity": "sha512-UlbRu4cAiGaIewkPyiRGJk0imDN2T3JjieT6spoL2UeSf5od4n5LB/mQ4ejmxhCFT1tYe8IvaFulzynWovsEFQ==",
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "scheduler": "^0.27.0"
       },
@@ -2978,6 +2986,7 @@
       "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
       "dev": true,
       "license": "Apache-2.0",
+      "peer": true,
       "bin": {
         "tsc": "bin/tsc",
         "tsserver": "bin/tsserver"
@@ -3023,6 +3032,7 @@
       "integrity": "sha512-BxAKBWmIbrDgrokdGZH1IgkIk/5mMHDreLDmCJ0qpyJaAteP8NvMhkwr/ZCQNqNH97bw/dANTE9PDzqwJghfMQ==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "esbuild": "^0.25.0",
         "fdir": "^6.5.0",
@@ -3113,21 +3123,6 @@
       "integrity": "sha512-a4UGQaWPH59mOXUYnAG2ewncQS4i4F43Tv3JoAM+s2VDAmS9NsK8GpDMLrCHPksFT7h3K6TOoUNn2pb7RoXx4g==",
       "dev": true,
       "license": "ISC"
-    },
-    "node_modules/yaml": {
-      "version": "2.8.1",
-      "resolved": "https://registry.npmjs.org/yaml/-/yaml-2.8.1.tgz",
-      "integrity": "sha512-lcYcMxX2PO9XMGvAJkJ3OsNMw+/7FKes7/hgerGUYWIoWu5j/+YQqcZr5JnPZWzOsEBgMbSbiSTn/dv/69Mkpw==",
-      "dev": true,
-      "license": "ISC",
-      "optional": true,
-      "peer": true,
-      "bin": {
-        "yaml": "bin.mjs"
-      },
-      "engines": {
-        "node": ">= 14.6"
-      }
     }
   }
 }

webapp/app.ironcalc.com/frontend/src/App.tsx

@@ -227,16 +227,19 @@ const Wrapper = styled("div")`
 `;
 
 const DRAWER_WIDTH = 264;
-const MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE = 440;
+export const MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE = 768;
 
 const MainContent = styled("div")<{ isDrawerOpen: boolean }>`
-  margin-left: ${({ isDrawerOpen }) => (isDrawerOpen ? "0px" : `-${DRAWER_WIDTH}px`)};
-  width: ${({ isDrawerOpen }) => (isDrawerOpen ? `calc(100% - ${DRAWER_WIDTH}px)` : "100%")};
+  margin-left: ${({ isDrawerOpen }) =>
+    isDrawerOpen ? "0px" : `-${DRAWER_WIDTH}px`};
+  width: ${({ isDrawerOpen }) =>
+    isDrawerOpen ? `calc(100% - ${DRAWER_WIDTH}px)` : "100%"};
   display: flex;
   flex-direction: column;
   position: relative;
   @media (max-width: ${MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE}px) {
-    ${({ isDrawerOpen }) => isDrawerOpen && `min-width: ${MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE}px;`}
+    ${({ isDrawerOpen }) =>
+      isDrawerOpen && `min-width: ${MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE}px;`}
   }
 `;
 
@@ -247,7 +250,7 @@ const MobileOverlay = styled("div")`
   right: 0;
   bottom: 0;
   background-color: rgba(255, 255, 255, 0.8);
-  z-index: 1;
+  z-index: 100;
   cursor: pointer;
 
   @media (min-width: ${MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE + 1}px) {

webapp/app.ironcalc.com/frontend/src/components/FileBar.tsx

@@ -3,6 +3,7 @@ import type { Model } from "@ironcalc/workbook";
 import { IconButton, Tooltip } from "@mui/material";
 import { CloudOff, PanelLeftClose, PanelLeftOpen } from "lucide-react";
 import { useLayoutEffect, useRef, useState } from "react";
+import { MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE } from "../App";
 import { FileMenu } from "./FileMenu";
 import { HelpMenu } from "./HelpMenu";
 import { downloadModel } from "./rpc";
@@ -77,7 +78,7 @@ export function FileBar(properties: {
           {properties.isDrawerOpen ? <PanelLeftClose /> : <PanelLeftOpen />}
         </DrawerButton>
       </Tooltip>
-      {width > 440 && (
+      {width > MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE && (
         <FileMenu
           newModel={properties.newModel}
           newModelFromTemplate={properties.newModelFromTemplate}
@@ -92,7 +93,7 @@ export function FileBar(properties: {
           onDelete={properties.onDelete}
         />
       )}
-      {width > 440 && <HelpMenu />}
+      {width > MIN_MAIN_CONTENT_WIDTH_FOR_MOBILE && <HelpMenu />}
       <WorkbookTitleWrapper>
         <WorkbookTitle
           name={properties.model.getName()}
@@ -112,7 +113,8 @@ export function FileBar(properties: {
               <div style={{ fontWeight: "bold" }}>{cloudWarningText2}</div>
             </div>
           }
-          placement="bottom-start"
+          placement="bottom"
+          enterTouchDelay={0}
           enterDelay={500}
           slotProps={{
             popper: {