This example demonstrate the use of RadioButtonGroup tool. You can select mathematical calculation from the option list. 

Here is how you setup Calculate button on click event.

                       procedure TForm1.Button1Click(Sender: TObject);
                       Var
                           V1, V2, V : Variant;
                           N1, N2 : Real;
                       begin
                            V1:=Edit1.Text;
                            V2:=Edit2.Text;
                            N1:=Real(V1);
                            N2:=Real(V2);
                            V:=0;
                       { Checking which radio button is                        selected ....}                 

                            If RadioButton1.Checked Then
                               V:=N1+N2
                            Else If RadioButton2.Checked Then
                               V:=N1-N2
                            Else If RadioButton3.Checked Then
                               V:=N1*N2
                            Else 
                               V:=N1/N2;
                            Label4.Caption:=V;
                       end;

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