My Excel Workbook (2003 version_ includes two tabs (spreadsheets. The first
tab is an income statement. The second tab is a trial balance.

The first spreadsheet has one column of account numbers. The SUMIF function
is in the amount column to the right of the account number column and it
refers to the second spreadsheet account number column. The formula pulls
dollar amounts from that spreadsheet (Trial Balance) for each account number
found in the first spreadsheet.

This SUMIF function works in ever cell of the first spreadsheet except for
cells with one specific account number. There is no error message. It simply
returns a ZERO amount. Formatting is "general" for the account number
columns in both spreadsheets. The account number in question is exactly the
same in both spreadsheets.

Any ideas why this is happening?