It is an Array Formula. See
http://www.cpearson.com/excel/ArrayFormulas.aspx
for tons of info about array formulas.

Cordially,
Chip Pearson
Microsoft Most Valuable Professional
Excel Product Group, 1998 - 2009
Pearson Software Consulting, LLC
www.cpearson.com
(email on web site)



On Wed, 8 Jul 2009 09:04:01 -0700, XS
wrote:

I need to use the formula like

{=SUM(($B14='Namedata'!$M$3:$M$14707)*(W$5='Named ata'!$AC$3:$AC$14707)*('Namedata'!$B$3:$B$14707))}

What's the name of it?

It seems it reference some cell from other sheet to check whether the
criterias are fulfilled, if then SUM them?

Thanks.