Sub test()
a = -2
variable = [COLOR=blue]"RC15"
[/COLOR]Cells(3 + a, 9[COLOR=blue]).Formula[/COLOR] = "=(1/2*R4C4+SUM(R5C4:" & variable & ")+1/2*R[12]C[-5])/R2C6"
End Sub
Sub test1()
a = -2
variable = [COLOR=blue]15
[/COLOR]Cells(3 + a, 9).[COLOR=blue]Formula[/COLOR] = "=(1/2*R4C4+SUM(R5C4:[COLOR=blue]RC[/COLOR]" & variable & ")+1/2*R[12]C[-5])/R2C6"
End Sub