var
  myDate : TDateTime;
begin
  // Set up our date just before the end of the year 2000
  myDate := EncodeDate(2000, 12, 30);
  ShowMessage('myDate = '+DateToStr(myDate));
  // Add 10 days to this date
  myDate := IncDay(myDate, 10);
  ShowMessage('myDate + 10 days = '+DateToStr(myDate));
  // Subtract 12 days from this date
  myDate := IncDay(myDate, -12);
  ShowMessage('myDate - 12 days = '+DateToStr(myDate));
end;

procedure TForm1.Button1Click(Sender: TObject);
var  myDate,myDate1 : TDateTime;
angka : integer;
begin
mydate := datetimepicker1.Date;
angka:= strtoint(edit1.Text);
myDate1 := myDate + angka ;
datetimepicker2.Date:= mydate1;
end;