"tompl" wrote:
It's a paren thing, try this:
=SUMPRODUCT((LEFT($F$4:$F$1004,2)="SM")
*($B$4:$B$1004))

Parentheses are not required around the range B4:B1004. I saw no syntax
error in Chris's original posting, to wit:

=SUMPRODUCT((LEFT($F$4:$F$1004,2)="SM")*$B$4:$B$10 04)

You should try it before commenting.