custom formula data validation

I'm having a senior moment evidently...

I'm trying to do data validation on cell x9
I have a min formula in cell z3 and a max formula in cell aa3.

The value in x9 must either be 0 or between z3 and aa3 inclusive.
So if the formula value in z3 is 130 and the max formula value in aa3 is 150, the only valid values in x9 are 0, and 130-150.

thanks

Hi mwc0914,

Let me know if entering (or copy and pasting) the following into the formula text box on the Data Validation dialog does the job:

=OR(X9=0,AND(X9>=Z3,X9<=AA3))

HTH

Robert