I'm not sure SUMPRODUCT is the right formul as i'm not trying to multiply
anything.

The data looks like this;

Source Downloads
10155 200
10156 300
10157 400
10158 500
10159 600

and i'm trying to write a formula that will give me the sum of the downloads
for 10155, 10156 and 10158 (1000)

I've tried both VLOOKUP and SUMIF with arrays
(=VLOOKUP({10156,10155,10158},A1:A5,2,FALSE) and
=SUMIF(A1:A5,{10156,10155,10158},B1:B5) respectively) but neither of these
give me the answer i'm looking for.

Cheers
Stuart