Hello Bob,

My email to your webmaster account bounced back.

I suggested to change your explanation / example for SUNPORODUCT for
an OR condition to change from

=SUMPRODUCT((A1:A10="Ford")+(B1:B10="June"))

to

=SUMPRODUCT(SIGN((A1:A10="Ford")+(B1:B10="June")))

because Fords in June would get double counted.

Kind regards,
Bernd