hi all,
I'm trying to make a summary sheet for my inventory sheet that will tell me
the total #of product (types a, b, c...) produced in a certain month. My
inventory sheet looks something like this:

Month Product
1 a
1 a
1 b
2 a
3 a
3 c

For my summary, say I want to enter the month of interest in cell c1. So, if
I'm interested in month 1, the cell in which my formula is in will spit out 3
as the total number of product produced.
I tried both =sumproduct((month(b2:b6)=c1)*1) and
=sumproduct((a2:a6(b2:b6)=c1)*1) which give me #value and #ref errors,
respectively. What am I doing wrong? Is there another formula I could try?

Thanks in advance.