procedure TForm1.GridSumaDrawCell(Sender: TObject; ACol, ARow: Longint;
  ARect: TRect; State: TGridDrawState);
var
  dx: integer;
begin
  with (Sender as TStringGrid).Canvas do
  begin
    Font := GridSuma.Font;
    Pen.Color := clBlack;
    if (ACol = 0) or (ARow = 0) then
    begin
      { Рисуем заголовок }
      Brush.Color := clBtnFace;
      FillRect(ARect);
      TextOut(ARect.Left, ARect.Top, GridSuma.Cells[ACol, ARow])
    end
    else
    begin
      { Рисуем ячейку с правым выравниванием }
      Brush.Color := clWhite;
      FillRect(ARect);
      dx := TextWidth(GridSuma.Cells[ACol, ARow]) + 2;
      TextOut(ARect.Right - dx, ARect.Top, GridSuma.Cells[ACol, ARow])
    end
  end
end;