Report multiplication/sum query

[asdfg]

I have 2 fields...'quantity' and 'usage'

I have grouped the report by site
The detail of each site has both fields.
I can easily list both fields and insert another field, 'total', which is
the quantity*usage.
I now require the sum of the 'total' field in the group footer

Creating a field in the group footer with control source = sum([total]) does
not work.

any ideas?

 

[Duane Hookom]

You can't sum "controls" across sections. You can use:
=Sum([Quantity] * [Usage])