Roger-

That worked - thanks so much!

"Roger Govier" wrote:

Hi

Try
=SUMPRODUCT((Add!$A$2:$A$100=$A2)*(Add!$B$2:$B$100 =B$1)*(Add!$C$2:$C$100))-SUMPRODUCT((Subtract!$A$2:$A$100=$A2)*(Subtract!$B $2:$B$100=B$1)*(Subtract!$C$2:$C$100))

Copy across and down.

--
Regards

Roger Govier


"JWNJ" wrote in message
...
Roger-

Thanks for the suggestion, I can see how this would work in most
cases. I
should have mentioned my summary worksheet will be set-up slightly
different
from the add/subtract worksheets.

The summary needs to look like this:

Product/Size sm med lrg x-lrg
blue pants
red pants
yellow pants

How should the formula be changed to reflect this format?

Thanks again.

"Roger Govier" wrote:

Hi

On you summary sheet create a unique list of Products and sizes.
Assuming your sheets are called"Add" and "Subtract", and that the
values
entered in quantity column are positive on both sheets, enter the
following formula into cell C2 and copy down

=SUMPRODUCT((Add!$A$2:$A$100=A2)*(Add!$B$2:$B$100= B2)*(Add!$C$2:$C$100))-SUMPRODUCT((Subtract!$A$2:$A$100=A2)*(Subtract!$B$ 2:$B$100=B2)*(Subtract!$C$2:$C$100))

If the values on your Subtract sheet are negative, then add the
second
sumproduct formula to the first.

--
Regards

Roger Govier


"JWNJ" wrote in message
...
I need to develop a "current inventory" spreadsheet from two
existing
spreadsheets; one tracks add and the other tracks
substractions/sold.
Each
spreadsheet tracks product, size and quantity. Here's an example:

Product Size Quantity
Blue Pants Lrg 5
Red pants Sm 5
Blue Pants Med 6
Blue Pants Lrg 7

Information is entered into these spreadsheets as events happen.
So
multiple similar product/size combinations exist in both
spreadsheets.
My
challenge is adding up all the matching combinations in the two
spreadsheets
and then substracting the solds from the add. Also need to
consider
that
some product/size combinations have never sold - so these
combinations
would
not appear on the sold spreadsheet.

Thanks in advance for any suggestions.