I have searched around for an answer but have not found something that
specifially deals with my issue, so I apologize in advance if this was
already answered.

a b c d e
1 200701 200702 200703 200704
2 Promo1 1 2 3 4
3 Promo2 5 6 7 8
4 Promo3 9 10 11 12
5 Promo1 13 14 15 16
6 Promo1 17 18 19 20

I would like a function that sums the data associated with Promo1 during the
week of 200702.

Whatis the best way to do this?

Thanks in advance,
Chad