If by 'only work' you mean only count those rows satisfying the additional
criterion, just add another 'clause' with that requirement:
=SUMPRODUCT(--(Y$2:Y$80=Y83),--(Z$2:Z$80=Z83),--(AA$2:AA$80=AA83),--(AC$2:AC$80="ABC"))


"Barb Reinhardt" wrote:

I have this equation:

=SUMPRODUCT(--(Y$2:Y$80=Y83),--(Z$2:Z$80=Z83),--(AA$2:AA$80=AA83))

I want to modify it so that it will work only if AC$2:AC$80="ABC". What do
I need to do?

Thanks,
Barb Reinhardt