Since there is no spreadsheet ability in iWork '05, this would be difficult. CalcService by
Devon Technologies can add some basic calculations to a table in Pages, but I think what you want is beyond its abilities. You could copy & paste data from a spreadsheet into a Pages table. Since you have an iMac, take a look at AppleWorks. This can be done in a database. If you'd like to pursue that option, post a question in the
AppleWorks forum.
Peggy