I have an overview worksheet which requires some calculation done from 10
worksheets (which are 'sandwiched' between a dummy Start and End sheet).

Within each of the 10 w'sheets, it comprises the following table:
A B
1 X
2 Y
3 Z
4 Y
5 X

I have an Overview worksheet (placed in front of all the w'sheets) which has
a cell that calculates the following:
1) check column A for the number 1 in the 10 w'sheets,
2) if match, check the same row and count how many times "X" appeared in the
same row in all w'sheets.

I tried using this formula but didn't work (value returned as #NAME?):
=SUM((Start:End!A1:A10=1)*(Start:End!B1:B10="X"))

Anyone can help?