Nested Function - Receiving #DIV/0! - Need Masking Error Help

Good morning.

I have run into another dilema. I am using the following formula =IF(IsNumber(A20), (A20-A21)/A20,"-") and attempting to avoid (masking) receiving the #DIV/0! or #VALUE! errors. I need assistance with a nested function that will avoid these errors and just put a "-" (hyphen) in its place. FYI A lot of times there will be 0 in A20 and A21, so I need to mask the formula result. I have attempted to modify the previous assistance but still receive one or the other errors.

Thanks a bunch. Deanna

It worked great! You rock! Thanks a bunch for your help. Deanna