Converting Access Databases

I have been working on a database in Access 2000 and need to run it on an Access 97 computer. When I convert the database to 97, some (not all) of the calculation fields in a querry loose formating and I cannot change them back. The Access 97 system thinks they are text for formatting, whoever they do the math. It is very important that the numbers diplay correctly (percent with no decimal places). Any suggestions short of rewritting the database?