I have a question about the use of Sumproduct to match multiple
conditions. While the calculations work as expected when I follow the
guide at this site:

http://www.contextures.on.ca/xlFunct...tml#SumProduct

What is the difference between SUMPRODUCT(--(A1:A10=0)) and
SUMPRODUCT((A1:A10=0))?

I am confused by the -- syntax. I have looked around and can't seem to
find any explanation for what it means. If I don't include them in my
Sumproduct calculations, the answers are incorrect. What gives?


Marc