I want to sum the product of two arrays, as in
=sumproduct(A1:Z1,A2:Z2)

Is there an easy way to reverse the order of the second array?

That is, what I would like is essentially "=sumproduct(A1:Z1,Z2:A2)"
but of course that won't work, as excel always takes the range from left to
right.

Anybody know a clever way to do this without writing a VBA function?