procedure TForm1.AppOnMessage(var Msg: TMsg; var Handled: Boolean);
 var
  ccode: Word;
 begin
  case Msg.Message of
  WM_KEYDOWN, WM_KEYUP:
  begin
  if (GetKeyState(VK_NUMLOCK) >= 0) {NumLock not active} and
  ((Msg.lParam and $1000000) = 0) {not a gray key} then
  begin
  ccode := 0;
  case Msg.wParam of
  VK_HOME: ccode := VK_NUMPAD7;
  VK_UP: ccode := VK_NUMPAD8;
  VK_PRIOR: ccode := VK_NUMPAD9;
  VK_LEFT: ccode := VK_NUMPAD4;
  VK_CLEAR: ccode := VK_NUMPAD5;
  VK_RIGHT: ccode := VK_NUMPAD6;
  VK_END: ccode := VK_NUMPAD1;
  VK_DOWN: ccode := VK_NUMPAD2;
  VK_NEXT: ccode := VK_NUMPAD3;
  VK_INSERT: ccode := VK_NUMPAD0;
  VK_DELETE: ccode := VK_DECIMAL;
  end; {Case}
  if ccode <> 0 then
  Msg.wParam := ccode;
  end; {If}
  end; {Case Msg.Message}
  end; {Case}
 end;
 procedure TForm1.FormCreate(Sender: TObject);
 begin
  Application.OnMessage := AppOnMessage;
 end;