Bob, I am studying your wonderful article on sumproduct. I have this:

A B
1 Make Month
2 Ford June
3 Ford June
4 Ford May
5 Ford June
6 Renault June
7 Renault June
8 BMW June
9 BMW May
10 BMW June

The question is, how many cars were either Fords or were sold in June?
I used
=SUMPRODUCT((A1:A10="Ford")+(B1:B10="June"))
expecting to get 8. Yet, I get 11.
I was expecting + to work like logical or, but it worked like arithmetic
plus.
Did I miss something? Or, how can I fix this to get the expected answer?
James