Sum Product is showing 0 when i use f9 to evaluate, it shows 1.

Here's an ARRAY formula (applied by pressing Ctrl + Shift + Enter) that seems to work:

Formula:

=SUM(IFERROR(IF(WEEKNUM(A1,2)=WEEKNUM(LEFT(C1:C3,FIND("-",C1:C3)-2),2),1,0),0))

I don't use SUMPRODUCT much, so not sure why that is not working.

- Moo