Hi,

I have never used the double negative signs in any formula. I have come
across it in several Q&A in var. userforums though, so however obvious
it may be (to the the rest of you), please excuse my ignorance.

I need an explanation, what is the purpose, and the logics behind, the
double negative signs?

By testing the formula below, I see the effect but I still don't get it :-(

T.i.a.

Helge

Dave F wrote:
Two options if you don't want to use SUMIF:

1) Use a pivot table. See here for more info:
http://www.cpearson.com/excel/pivots.htm

2) Use SUMPRODUCT: =SUMPRODUCT(--(A1:A100="January"),--(B1:B100)) etc.

Dave