Modifying the contents of a cell using the cell itself

Hello, Is it possible to change the contents of a numeric cell by adding a 1 for example using the contents of the cell itself like:
C1=15 and D1=1
If D1=1 then C1=C1+1
Hope I was clear. Thanks you anyway.
Anarna

[Derek]

Hi
I don't think you can do this by formula but you can do it by vb code:

If Range("D1").Value = 1 Then Range("C1").Value = Range("C1").Value + 1

(code is all on one line)
hope this helps
regards
Derek