unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)
    BtnPlus: TButton;
    BtnMinus: TButton;
    EdtNumber1: TEdit;
    EdtNumber2: TEdit;
    LblOperation: TLabel;
    Label2: TLabel;
    LblResult: TLabel;
    procedure BtnMinusClick(Sender: TObject);
    procedure BtnPlusClick(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.BtnPlusClick(Sender: TObject);
Var
  Number1, Number2, NumberResult : Integer;
  begin
   LblOperation.Caption:='+';
   Number1 := StrToInt(EdtNumber1.Text);
   Number2 := StrToInt(EdtNumber2.Text);
   NumberResult := Number1+Number2;

   LblResult.caption := IntToStr(NumberResult);
end;

procedure TForm1.BtnMinusClick(Sender: TObject);
Var
  Number1, Number2, NumberResult : Integer;
begin
  LblOperation.Caption:='-';
     Number1 := StrToInt(EdtNumber1.Text);
   Number2 := StrToInt(EdtNumber2.Text);
   NumberResult := Number1-Number2;

   LblResult.caption := IntToStr(NumberResult);
end;

end.