Hi Lori,

I modified your approach a little bit, so that I've got now what I
need.
"Blaetter" is a named range, where I have stored all sheets which have
to be processed.
This is the sum of a multiplication of all D24 cells with all B81
cells devided by all B96 cells,
let's say an operation with three arrays across the sheets contained
in "Blaetter" and then totaled.

=SUM(N(INDIRECT("'"&Blaetter&"'!D24"))*N(INDIRECT( "'"&Blaetter&"'!
B81"))/N(INDIRECT("'"&Blaetter&"'!B96"))).

Thank you to get me started.

Werner