Try the following formula...

=SUMPRODUCT(SUMIF(INDIRECT("'"&ROW(INDIRECT("1:"&$ C$1))&"'!"&CELL("address",A1)),"<"))

OR

=SUMPRODUCT(SUMIF(INDIRECT("'"&ROW(INDIRECT("1:"&$ C$1))&"'!"&ADDRESS(ROW(A1),COLUMN(A1),4)),"<"))

Hope this helps!

Avner Wrote:
It Helps !

I have to understand what it means in order to keep c1=x absolute and
a1 relative so i can copy it across rows and columns.

thanks again
avner


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