I needed a formula (that I was able to find on this group, btw). The formula
from the gropu was:

=sumproduct(--(B2:B10=1),--(F2:F10="Completed"))

My question is, what does the -- do, and can I find more information about
this in the help files? If it is in help, what is it called, as I haven't
been able to find anything about it - even when looking at the sumproduct
help information.

Thanks,