Without much data, difficult to answer without assumptions, but here
goes...
Assuming each sheet is named bu month and you want to sum the same cell
(let's say B5) in all tabs, Insert a new tab at the end, named Year
summary.

In Cell B5, on the Year summary, your formula would be
=sum(Jan:Dec!B5)
This will of course only work if your furthest left tab is named Jan
and your second last to the right is named Dec with the Year Summary
being farthest rught.

Let me know if this works for you or provide more information regarding
how sheets are set up.


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flydecoder
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