Hi; I'd like to get the sumproduct of two cells, d19 and d20, across
worksheets. For instance, Lets say there are two worksheets; The first
worksheet is 10 and the second one is 14. Thus, I've tried using the
following formula:

=SUMPRODUCT('10:14'!D19:'10:14'!D20)

which produces an error.

Thanks in advance.