=sumif(Sheet1!A:A,"12345",Sheet1!B:B)+Sumif(Sheet2 !A:A,"12345",Sheet2!B:B)

assumes the values you want to subtract are negative values. Sums
corresponding values found in column B for cells in column A containing
12345. Adjust to match you actual ranges.

--
Regards,
Tom Ogilvy



"CV0613" wrote:

Please help, I am looking to create an inventory worksheet that I need a
vlookup formula for a value across multiple worksheets and sum the difference
of the returned values for that specific argument.

EX)
Lookup piece 12345 and the piece 12345 appears in multiple cells in two
other worksheets. How do I sum the difference of all the value additions
minus subtractions and return in a specific column with a formula.

Any help you can give is greatly appreciated.

Regards,
Christine