Now I have this report wher a certain field is populated by multiplying 2 fields from 2 different tables. At the group footer I want the summation to display.

I have the fomular working for indiviual records I pull to the report, but when it comes to summation it adds extra figures (i.e 20 if they are 2 records , 30 if thay are 3 records ...) and I can't figure where they come from. Can anyone tell me what am I doing wrong?