Say, sumproduct(A, B)=a1*b1 + a2*b2 + a3*b3, now I have many columns C, D,..., e.g. c1 checked, c2 unchecked, c3 checked; d1 unchecked, d2 checked, d3 checked;
Now I need a formulae which I want to put in a cell of each of column C, D... to compute a conditional sum product to get a1*b1 + a3*b3 and a2*b2 + a3*b3 respectively.
This can be used in my nutrition calculation table of daily intake.
Thanks a lot.