Depending on if the cells are all in a row, let's say the cell to subtract
from is A1 cells are A2 - A33, then you type =A1-sum(A2:A33). If not
consecutive, type =A1-(each cell to subtract from it)
What does your formula look like? Post a copy here, I'll bet the fix is simple.
I have no problem with a formula like this
=A1-A2-A3-A4-A5-A6-A7-A8-A9-A10-A11-A12-A13-A14-A15-A16-A17-A18-A19-A20-A21-A22-A23-A24-A25-A26-A27-A28-A29-A30-A31-A32-A33-A34-A35-A36-A37-A38
although it could also have been written as:
=A1-SUM(A2:A38)
so maybe we can do something similar for you.