Formula R1C1 problem

[yjmmay34]

Hi, all. I need to use a loop to run through the necessary column, and if match the condition, then autofill the column's data to desired column. but when the macro run to ActiveCell.FormulaR1C1 = "=RC[-123+i]" , it got error msg says : run time error"1004" Application-defined or object-defined error? how should i modify this problem?? Please help. Thank you!

i = 28
        Do While i <= 41
         If range("GP3").Value = Cells(4, i).Value Then
          If range("GP4").Value = Cells(5, i).Value Then
            range("GP8").Select
            ActiveCell.FormulaR1C1 = "=RC[-123+i]"
            selection.AutoFill Destination:=range(Cells(8, "GP"), Cells(GrandTotalRowCount, "GP")), Type:=xlFillDefault
          End If
         End If
         i = i + 1
        Loop

[lecxe]

Try:

ActiveCell.FormulaR1C1 = "=RC[" & (-123 + i) & "]"

[yjmmay34]

Thank you so much lecxe. it can work perfectly. Have a nice day!