=SUM('R5:R10'!AV5:AW11)/COUNTIF('R5:R10'!AV5:AW11,"0")

COUNTIF doesn't accept 3d references.

Try one of these

=SUM('R5:R10'!AV5:AW11)/SUMPRODUCT(COUNTIF(INDIRECT("'R"&{5,6,7,8,9,10}&"' !AV5:AW11"),"0"))

=SUM('R5:R10'!AV5:AW11)/SUMPRODUCT(COUNTIF(INDIRECT("'R"&ROW(INDIRECT("5:1 0"))&"'!AV5:AW11"),"0"))

--
Biff
Microsoft Excel MVP


"Brandy" wrote in message
...
Hello All,

I have a 50 worksheet file that has a summary on each page that I would
like
to summarize again on a summary page into broader categories. The summary
value is a formula in a merged cell and right now I have
=SUM('R5:R10'!AV5:AW11)/COUNTIF('R5:R10'!AV5:AW11,"0"). The problem is
when
I add in values it doesn't change the number for me.

Any idea what I am doing wrong?

Any help would be greatly appreciated.

Thanks,

B