I'm not sure what formula i need to use.

A B C D

1 Pack Description Qty Order: Store 1 Qty Order: Store 2
2 15 4" Ivy 30 15
3 12 6" Ivy 24 12
4 6 8" Ivy 18 6
5
6 Total Cases: 7 3

Basically, the long version of C6 is =sum(c2/a2, c3/a3, c4/a4)

i have an entire page of this, i want to find the total cases ordered
per store.

Thanks for your help.