diff --git a/applications/lazstats/source/forms/tools/calculatorunit.pas b/applications/lazstats/source/forms/tools/calculatorunit.pas
index 0bc950837..08d30e9c9 100644
--- a/applications/lazstats/source/forms/tools/calculatorunit.pas
+++ b/applications/lazstats/source/forms/tools/calculatorunit.pas
@@ -5,7 +5,7 @@ unit CalculatorUnit;
 interface
 
 uses
-  Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
+  Classes, SysUtils, Forms, Controls, Graphics, Dialogs,
   StdCtrls, Math,
   FunctionsLib, Globals;
 
@@ -123,6 +123,11 @@ var
 
 implementation
 
+{$R *.lfm}
+
+uses
+  Utils;
+
 { TCalculatorForm }
 
 procedure TCalculatorForm.FormShow(Sender: TObject);
@@ -144,15 +149,17 @@ end;
 
 procedure TCalculatorForm.log10btnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := log10(X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := log10(X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.MemInBtnClick(Sender: TObject);
 begin
-  Xmemory := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
+  if TryStrToFloat(XEdit.Text, Xmemory) then
+    XEdit.Text := '';
 end;
 
 procedure TCalculatorForm.MemOutBtnClick(Sender: TObject);
@@ -161,33 +168,45 @@ begin
 end;
 
 procedure TCalculatorForm.MemPlusBtnClick(Sender: TObject);
+var
+  value: Double;
 begin
-  stack[NoStack] := stack[NoStack] + StrToFloat(XEdit.Text);
-  NoStack := NoStack + 1;
-  NEdit.Text := IntToStr(NoStack);
-  XEdit.Text := '';
+  if TryStrToFloat(XEdit.Text, value) then
+  begin
+    stack[NoStack] := stack[NoStack] + value;
+    NoStack := NoStack + 1;
+    NEdit.Text := IntToStr(NoStack);
+    XEdit.Text := '';
+  end;
 end;
 
 procedure TCalculatorForm.multbtnClick(Sender: TObject);
 begin
-  TempX := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
-  operation := 2; // multiply
+  if TryStrToFloat(XEdit.Text, TempX) then
+  begin
+    XEdit.Text := '';
+    operation := 2; // multiply
+  end;
 end;
 
 procedure TCalculatorForm.natlogbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := ln(X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := ln(X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.nfactorialbtnClick(Sender: TObject);
-var n : integer;
+var
+  n : integer;
 begin
-     n := StrToInt(XEdit.Text);
-     n := factorial(n);
-     XEdit.Text := IntToStr(n);
+  if TryStrToInt(XEdit.Text, n) then
+  begin
+    n := factorial(n);
+    XEdit.Text := IntToStr(n);
+  end;
 end;
 
 procedure TCalculatorForm.ninebtnClick(Sender: TObject);
@@ -197,14 +216,16 @@ end;
 
 procedure TCalculatorForm.nPrbtnClick(Sender: TObject);
 begin
-  operation := 7;
-  Xint := StrToInt(XEdit.Text);
-  XEdit.Text := '';
+  if TryStrToInt(XEdit.Text, Xint) then
+  begin
+    operation := 7;
+    XEdit.Text := '';
+  end;
 end;
 
 procedure TCalculatorForm.onebtnClick(Sender: TObject);
 begin
-XEdit.Text := XEdit.Text + '1';
+  XEdit.Text := XEdit.Text + '1';
 end;
 
 procedure TCalculatorForm.PeriodBtnClick(Sender: TObject);
@@ -224,9 +245,11 @@ end;
 
 procedure TCalculatorForm.sinbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := sin(DegToRad(X));
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := sin(DegToRad(X));
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.sixbtnClick(Sender: TObject);
@@ -236,37 +259,47 @@ end;
 
 procedure TCalculatorForm.sqrbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := X * X;
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := X * X;
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.sqrtbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := sqrt(X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := sqrt(X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.subtractbtnClick(Sender: TObject);
 begin
-  TempX := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
-  operation := 3;  // subtract
+  if TryStrToFloat(XEdit.Text, TempX) then
+  begin
+    XEdit.Text := '';
+    operation := 3;  // subtract
+  end;
 end;
 
 procedure TCalculatorForm.tanbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := tan(DegToRad(X));
-  XEdit.Text := FloatToStr(X);
+  if TryStrTofloat(XEdit.Text, X) then
+  begin
+    X := tan(DegToRad(X));
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.tentoxbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := power(10,X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := power(10,X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.threebtnClick(Sender: TObject);
@@ -286,14 +319,16 @@ end;
 
 procedure TCalculatorForm.ytopowerxbtnClick(Sender: TObject);
 begin
-  operation := 5;
-  tempX := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
+  if TryStrToFloat(XEdit.Text, tempX) then
+  begin
+    operation := 5;
+    XEdit.Text := '';
+  end;
 end;
 
 procedure TCalculatorForm.ZeroBtnClick(Sender: TObject);
 begin
-XEdit.text := XEdit.Text + '0';
+  XEdit.text := XEdit.Text + '0';
 end;
 
 procedure TCalculatorForm.ClearEntryBtnClick(Sender: TObject);
@@ -303,37 +338,47 @@ end;
 
 procedure TCalculatorForm.CombobtnClick(Sender: TObject);
 begin
-  operation := 6;
-  tempX := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
+  if TryStrToFloat(XEdit.Text, tempX) then
+  begin
+    operation := 6;
+    XEdit.Text := '';
+  end;
 end;
 
 procedure TCalculatorForm.cosbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := cos(DegToRad(X));
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := cos(DegToRad(X));
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.AddbtnClick(Sender: TObject);
 begin
-  TempX := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
-  operation := 4; // add
+  if TryStrToFloat(XEdit.Text, TempX) then
+  begin
+    XEdit.Text := '';
+    operation := 4; // add
+  end;
 end;
 
 procedure TCalculatorForm.ChangeSignBtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := -1.0 * X;
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := -X;
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.etoxbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := power(2.71828182845905,X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := exp(X); //power(2.71828182845905, X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.PiBtnClick(Sender: TObject);
@@ -344,24 +389,28 @@ end;
 
 procedure TCalculatorForm.absbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := abs(X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := abs(X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.VarBtnClick(Sender: TObject);
-VAR
-  Sum, SSQ : double;
-  Ncount : double;
-  i, index : integer;
+var
+  Sum, SSQ: double;
+  NCount: double;
+  i, index: integer;
 begin
-  Ncount := StrToFloat(NEdit.Text);
-  index := StrToInt(NEdit.Text);
+  if not TryStrToFloat(NEdit.Text, NCount) then    // wp: why read the same Edit into two variables?
+    exit;
+  if not TryStrToInt(NEdit.Text, index) then
+    exit;
   Sum := 0.0;
   SSQ := 0.0;
-  if Ncount < 1 then
+  if NCount < 1 then
   begin
-    ShowMessage('No values in stack memory');
+    ErrorMsg('No values in stack memory');
     exit;
   end
   else
@@ -385,12 +434,14 @@ Var
   Ncount : double;
   i, index : integer;
 begin
-  Ncount := StrToFloat(NEdit.Text);
-  index := StrToInt(NEdit.Text);
+  if not TryStrToFloat(NEdit.Text, NCount) then     // wp: why two variables?
+    exit;
+  if not TryStrToInt(NEdit.Text, index) then
+    exit;
   Sum := 0.0;
   if Ncount < 1 then
   begin
-    ShowMessage('No values in stack memory');
+    ErrorMsg('No values in stack memory');
     exit;
   end
   else
@@ -407,8 +458,10 @@ VAR
   Ncount : double;
   i, index : integer;
 begin
-  Ncount := StrToFloat(NEdit.Text);
-  index := StrToInt(NEdit.Text);
+  if not TryStrToFloat(NEdit.Text, NCount) then     // wp: why two variables?
+    exit;
+  if not TryStrToInt(NEdit.Text, index) then
+    exit;
   Sum := 0.0;
   SSQ := 0.0;
   if Ncount < 1 then
@@ -434,9 +487,11 @@ end;
 
 procedure TCalculatorForm.dividebtnClick(Sender: TObject);
 begin
-  TempX := StrToFloat(XEdit.Text);
-  XEdit.Text := '';
-  operation := 1; // //divide
+  if TryStrToFloat(XEdit.Text, TempX) then
+  begin
+    XEdit.Text := '';
+    operation := 1; // //divide
+  end;
 end;
 
 procedure TCalculatorForm.eightbtnClick(Sender: TObject);
@@ -445,52 +500,59 @@ begin
 end;
 
 procedure TCalculatorForm.EqualBtnClick(Sender: TObject);
-Var x1, x2 : double;
+var
+  x1, x2: double;
+  editVal: Double;
 begin
+  if not TryStrToFloat(XEdit.Text, editVal) then
+    exit;
+
   case (operation) of
        1 : begin // divide operation
          x1 := tempX;
-         x2 := x1 / StrToFloat(XEdit.Text);
+         x2 := x1 / editVal;
          XEdit.Text := FloatToStr(x2);
        end;
        2 : begin // nultiply operation
          x1 := tempX;
-         x2 := x1 * StrToFloat(XEdit.Text);
+         x2 := x1 * editVal;
          XEdit.Text := FloatToStr(x2);
        end;
        3 : begin
          x1 := tempX; // subtract operation
-         x2 := x1 - StrToFloat(XEdit.Text);
+         x2 := x1 - editVal;
          XEdit.Text := FloatToStr(x2);
        end;
        4 : begin
          x1 := tempX; // Add operation
-         x2 := x1 + StrToFloat(XEdit.Text);
+         x2 := x1 + editVal;
          XEdit.Text := FloatToStr(x2);
        end;
        5 : begin  // y to the X power (Y stored in tempx first, x in register)
-         X := StrToFloat(XEdit.Text);
-         X := power(tempX,X);
+         X := power(tempX, editVal);
          XEdit.Text := FloatToStr(X);
        end;
        6 : begin  // combinations of x things out of N
-           X := StrToFloat(XEdit.Text);
-           X := combos(X,tempX);
+           X := combos(editVal,tempX);
            XEdit.Text := FloatToStr(X);
        end;
        7 : begin // permutations of x things out of N
-           Xint2 := StrToInt(XEdit.Text);
-           Xint := factorial(Xint) div (factorial(Xint - Xint2));
-           XEdit.Text := IntToStr(Xint);
+           if TryStrToInt(XEdit.Text, XInt2) then
+           begin
+             Xint := factorial(Xint) div (factorial(Xint - Xint2));
+             XEdit.Text := IntToStr(Xint);
+           end;
        end;
   end;
 end;
 
 procedure TCalculatorForm.expbtnClick(Sender: TObject);
 begin
-  X := StrToFloat(XEdit.Text);
-  X := exp(X);
-  XEdit.Text := FloatToStr(X);
+  if TryStrToFloat(XEdit.Text, X) then
+  begin
+    X := exp(X);
+    XEdit.Text := FloatToStr(X);
+  end;
 end;
 
 procedure TCalculatorForm.fivebtnClick(Sender: TObject);
@@ -498,8 +560,6 @@ begin
   XEdit.Text := XEdit.Text + '5';
 end;
 
-initialization
-  {$I calculatorunit.lrs}
 
 end.