If you try to do arithmetic with strings (even empty strings like ""), then
you'll get errors.

I'd use:
=if(c7=e3,"",c7-e3)
or
=if(count(c7,e3)<2,"",if(c7=e3,"",c7-e3))

=sum() doesn't help in your formula.

And make sure that you have calculation set to automatic:
In xl2003 menus:
tools|Options|calculation tab



Misty wrote:

I am using excel 2007. Creating a inventory spreadsheet to show initial
quantity and then a continous running total when used. I created a formula to
hide 0 values.
Example =if(sum(c7-e3)=0,"",(sum(c7-e3))).
When I try to copy-my options are copy cell, with formatting or without. It
only copies down the existing answer from the previous cell or I get an error
#value!.
Help!
Thanks

--

Dave Peterson