Brad;
No reason for this. Only I can think of is that the sheet is corrupted some
how. Suggestion, delete the second sheet and try on a new one.

Argy

"Brad" wrote:

Excel 2007

On one sheet
=date(2008,13,1) provides the correct answer of 1/1/2009

copy that equation to a different sheet (in the same workbook) provides the
incorrect answer of #NUM!

copy that equation to a third sheet (in the same workbook) provides the
correct answer of 1/1/2009

Can't figure why I'm getting the #NUM!. Any suggestions?