By David Hager
Say, for instance, that you have 4 sheets named A-D and on each there is a list with range of A1:E21. If you filter each list and use the following formula:
you will get the sum of each list for column C. The best part is that the sheets do not have to be contiguous.
It is important to note that a similar formula does not return a result, although you might expect it to.