FpSpread1.EnableCrossSheetReference = true;
FpSpread1.ActiveSheetView.Cells[2, 2].Formula = "FirstRoundData!A2 + SecondRoundData!A2";
FpSpread1.EnableCrossSheetReference = True
FpSpread1.ActiveSheetView.Cells(2, 2).Formula = "FirstRoundData!A2 + SecondRoundData!A2"