Stop hunting through cells manually; Excel already knows where your formula broke.
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How to use Excel tables to automate formulas and prevent broken ranges
Most spreadsheet problems come from static cell ranges—Excel tables replace them with dynamic, self-managing data structures.
That indicates a SUM formula (adding things up) for all the sheets that are titled Y1 to Y10 (so 10 years' worth), and looking at cell B3 in each. The result will be the sum of all 10 years.
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