Hello, I am having a problem with a formula in an Excel spreadsheet that I
have been using for two years, but for some unknown reason it has stopped
working.

About every ten months I copy this worksheet with all formulas to a new tab
in the workbook. This is the very thing I have done here. The total it
usually derives has not been calculated and has been replaced by the figure
it is meant to subtract and made it a negative value.

I will enclose a copy of the formula here in the hope somebody can see what
it is doing differently, however it is exactly the same formula I have been
using in previous worksheets.

=IF(ISERROR(VLOOKUP(99999999,C7:CB48,1)-VLOOKUP
99999999,B7:B48,1)),0,VLOOKUP(99999999,C7:CB48,1)-VLOOKUP(99999999,B7:B48,1))
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Steven.

In God we trust, all others we virus scan.