Thanks to both of you!! I had been researching for a week before I joined this site, but now I know why I couldn't find anything: because the SUMPRODUCT used in this fashion is a bit of a workaround. I tried the SUMIF just to test my understanding and apply a similar function, but the SUMPRODUCT fits the bill in this case because it treats a blank cell differently than a cell that has zero. In my real-life scenario, there is a difference because a blank cell should be ignored (as I have not received data for those), whereas a cell with zero should be computed because that's the true value. So because of you two, I have two additional tools in my belt to use for future spreadsheets!!!