[NumLock]

Код:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

procedure lost(num1, num2: String);

implementation

{$R *.dfm}

procedure lost(num1, num2: String);
begin
  try
    ShowMessage(IntToStr(StrToInt(num1)+StrToInt(num2)));
  except
    ShowMessage('Oops');
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  lost(Edit1.Text, Edit2.Text);
end;

end.

Код:

unit Unit2;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm2 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

uses Unit1;

{$R *.dfm}

procedure TForm2.Button1Click(Sender: TObject);
begin
  lost(Edit1.Text, Edit2.Text);
end;

end.