Errata....

On Mar 8, 6:12 pm, "joeu2004" wrote:
First of all, you probably want:
AVERAGE(ESP1!F24,ESP2!F24,LV!F24,LA!F24,RAT!F24,SF 1!F24,SF2!F24,SF3!
F24,TAO*S!F24)
[....]
AVERAGE() probably returned #DIV/0! because AVERAGE() thinks that all
the cells are blank or contain non-numeric values (e.g. text).

Oops, my bad! I was thinking of __my__ form of AVERAGE().
AVERAGE(A1+...+A9) works just fine if all cells in the range are blank
(or zero). There is no problem with AVERAGE() if all the arguments
sum to zero. If any cell is non-numeric, the expression will returns
#VALUE!, and so does AVERAGE().