Hi,

Take
=IF(AND(K9=$K$20,$K$20=1), 1, 0)

or shorter in this special case - if inputs can only be 1 or 0
=--AND(K9,K20)

BTW: The first formula will return 1 only if both K9 and K20 are 1. If
one or both are not equal to 1 it will return 0. The second formula
will return 1 if both inputs are not equal to zero. This irrelevant if
inputs can only be 1 or 0 but think of empty cells or values like3, 4,
or 0.0001.

Regards,
Bernd