Looking at the CharityDonors db.  I am wanting to know how to do some calculations on the data.  For example, how would I go about calculating the total amount of donations paid by check?  Then, what percentage of that total paid by check did each donor pay.

Total donations by check = $XXX.OO
Smith donation by check = $XX.00  or 2.43% of Total
Jones donation by check = $XX.00 or 6.15% of Total....


I have been looking at using @XlookupSourceListAll but do not see how to "mix/combine" the information from the Donors and Donations forms.  Do I need to add a "Key" to the subform that ties into the Main form?

Am I waaaaay off base?

Thanks