You can just use SUM

=SUM(A1*C1,A2*C2,A4*C4)

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HTH

RP
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"jiang" wrote in message
...
dear all

a question about sumproduct function, in a sheet
A B C
1) 2 0 1
2) 4 5 6
3) 7 8 9
4) 10 11 12

Now I can use 2 sumproduct to make calculation,like
A1*C1+A2*C2 in one sumproduct
A4*C4 in another sumproduct
then I add result together.

My question is, is there anyway to make a formula
A1*C1+A2*C2+A4*C4. I could choose different array then define in more
detail
because sumproduct ask all array should have same dimension.

Thanks in advance.