WhilePrintingRecords calculations

I am using Crystal Version 9.0. I am in need of performing some calculations on some data. I cannot use the Running Total feature as I need ot make other additional calculations. I am instead using the 3 formulas with the WhilePrintingRecords and counting.

I have 2 variables to use. When I get to the footer section, I am trying to do some final calculations on the data to be displayed. I have the following below that I am trying to use. Because of the division, I need to be sure that I compensate for the 0 value. That is why I have the If...Then statement.

Regards

WhilePrintingRecords;
If
CurrencyVar Amount <> 0
then
((CurrencyVar Amount) - (CurrencyVar PastAmt))/(CurrencyVar Amount * 100)

What's your problem?

And didn't declare the variables?