Crystal Report sub-report expert advice needed.

Hi,
I created 2 seperate Crystal reports and each report performs its own calculations.
However, I need to multiply the output of Report 1 with the output of Report 2.
I created a new Crystal report and inserted Report 1 and Report 2 as sub-report 1 and sub-report 2 in my new Crystal report. The output of both sub-report 1 and sub-report 2 are numeric.
I need to find out how I can multiply the output of sub-report 1 and sub-report 2 so that the total is displayed on my main Crystal report.

Any help will be much appreciated.Sorry, I don't remember how exactly to do it but I am sure Crystal Report help has an answer to this. But why don't you do all calculations on the backend using stored procedure or a view and return ready to display result then using cumbersome and slow report facilities?