I have an excel spreadsheet with 3 tabs on the bottom. The first tab shows a summary of the invoices, dollar amounts, and patent #’s and different countries each patent refers to (multiple countries can apply to a single patent. On the second tab is the general list of patents on the the first the first column and the countries on the first row. I want to draw the total dollar amount for each patent and countries it applies to from the first tab with a formula. What is the best way to do so?