I have a listing of sales data for different regions for each month that has
the item running down column A. In column B I have the gross sells and in the
cell directly below that I have the quantity sold. As such

Region Product Data Sep Oct
Nov
North Widgets Gross Sales 100 120 110
Quantity 20
30 25
Trinkets Gross Sales 500 480
510
Quantity 100 80
105

And so it repeats with every region showing all the products we sell and the
sales for that region.

I am able to calculate the gross sales for each product using
=sumproduct((Product=Widgets)*(Data=Gross Sales)*Sep and I get the right
numbers. However, I don't know how to calculate the Quantity since it doesn't
have the name Widget (or whatever the product may be) in the same row.

How can I calculate the quantity sold for each product for all regions?

Thanks in advance.