unit Unit1;

{$mode objfpc}{$H+}

interface

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

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  a, b, c: single;
begin
  a := StrToFloat(Edit1.Text);
  b := StrToFloat(Edit2.Text);
  c := a + b;
  Edit3.Text := FloatToStr(c);
  Memo1.Lines.Add(Edit1.Text + ' + ' + Edit2.Text + ' = ' + Edit3.Text);
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  a, b, c: single;
begin
  a := StrToFloat(Edit1.Text);
  b := StrToFloat(Edit2.Text);
  c := a - b;
  Edit3.Text := FloatToStr(c);
  Memo1.Lines.Add(Edit1.Text + ' - ' + Edit2.Text + ' = ' + Edit3.Text);
end;

procedure TForm1.Button3Click(Sender: TObject);
var
  a, b, c: single;
begin
  a := StrToFloat(Edit1.Text);
  b := StrToFloat(Edit2.Text);
  c := a * b;
  Edit3.Text := FloatToStr(c);
  Memo1.Lines.Add(Edit1.Text + ' * ' + Edit2.Text + ' = ' + Edit3.Text);
end;

procedure TForm1.Button4Click(Sender: TObject);
var
  a, b, c: single;
begin
  a := StrToFloat(Edit1.Text);
  b := StrToFloat(Edit2.Text);
  c := a / b;
  Edit3.Text := FloatToStr(c);
  Memo1.Lines.Add(Edit1.Text + ' / ' + Edit2.Text + ' = ' + Edit3.Text);
end;

end.