vba sum coding

[Godders199]

I have the following vba which works, but i need to change the sum

For i = 1 To Cells(Rows.Count, "b").End(xlUp).Row
Range("ae" & i) = WorksheetFunction.Sum(Range("ad" & i & ":af" & i))
Next i

it needs to say
Range("ae" & i) = WorksheetFunction.Sum(Range("ad" & i & ":af" & i ":-y" & i))

when i add the subraction it errors..

I also need to add in the value in cell o8 on sheet 4 so effectlively the whole formula would be
(ad & i + Af & i - y & i)+cell o8 on sheet 4

if anyone can help ..

much appreciated.

 

[Nine Zero]

i suggest separating the values so have another Dim Integer with the value of range("Y" & i) then subtract it from the sum and update your Range("AE" & i).value