I figured it out, nevermind.

"Ted Metro" wrote:

I have a table of monthly sales by office so it looks something like this:

a b c
d e f etc.
1 city jan feb
mar apr may
2 denver 100 150 90
200
3 chicago 250 350 300
425
4 atlanta 175 130 125
150

I have a base month for every city and I want to add the three months
following the base month and then subtract the three month sum preceding the
base month.

So I have Denver's base as April in a separate cell and I want a formula
that will reference that base as April and know to add Denver's numbers for
May, June and July, and then subract the sum of Denver's Jan., Feb., and
March.

Likewise if I changed the value for Denver's base month to May then the
formula would add Denver's values for June, July and August, and then
subtract from that Denver's Feb., March, and April.

I could use an Hlookup and do 3 hlookups for the add partand another 3 for
the subtract part, but that's one ugly formula. Any ideas...?

Ted