unit Unit1;
  
interface
  
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;
  
type
  TForm1 = class(TForm)
    Label1: TLabel;
    Timer1: TTimer;
    Button1: TButton;
    Button2: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    
  public
    
  end;
  
var
  Form1: TForm1;
   time: TTime;
  timesec: TTime;
  
implementation
  
{$R *.dfm}
  
procedure TForm1.FormCreate(Sender: TObject);
begin
 time := StrToTime('00:00:00');
  timesec:= StrToTime('0:0:1');
  button1.Caption:='Старт' ;
  button2.Caption:='Стоп'  ;
end;
  
procedure TForm1.Timer1Timer(Sender: TObject);
begin
time:=time-timesec;
  Label1.Caption:=TimeToStr(time);
end;
  
procedure TForm1.Button1Click(Sender: TObject);
begin
Timer1.Enabled:=True ;
time := time+StrToTime('0:10:0')
end;
  
procedure TForm1.Button2Click(Sender: TObject);
begin
Timer1.Enabled:=False ;
  
end;
  
end.