Quote Originally Posted by ron2k_1 View Post
Welcome to the forum, this as an array may help. Note that it only works if the sheets are sorted in order (1,2,3,4... and not 1,3,2,4...). If they are not in order then you need to do a bit of more work.

=SUM(N(INDIRECT(ROW(INDIRECT(A1&":"&B1))&"!A1")))
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Note: INDIRECT does not seem to support 3D formulas, hence the above.
Thanx a lot Ron2k. what a fast reply. i have tried your formula n it seems, it doesn't calculated all. it only calculate the first sheet only. when i enter 1 on A1 and 2 on B1, the result is only the number on sheet "1" only. no matter what number i enter on B1, it shows the same result.

Please help me on this.