The terms in brackets in a sumproduct formula will be logical terms
and thus will return values of FALSE or TRUE. Using a single minus
will change these to 0 and -1, and a double minus converts them to 0
or 1, so they can be used in arithmetic. You can use them like this in
a SP formula:

=SUMPRODUCT(--(condition1),--(condition2),--(condition3))

but an alternative to this is:

=SUMPRODUCT((condition1)*(condition2)*(condition3) )

Hope this helps.

Pete

On Apr 4, 1:21*pm, Negda wrote:
In some example I saw the use of double dashes at the beginning:
=sumproduct( -- (....))

What does it mean? when I should use it and to avoid?