=AVERAGE(IF(Fri!A1:A6<0,Fri!A1:A6),IF(Sat!A1:A10< 0,Sat!A1:A10))

this is an array formula, so commit with Ctrl-Shift-Enter.

likewise for the other.

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HTH

Bob

"DaS" wrote in message
...
I have a tab for each day of the week with a summary tab. The summary tab
is
going to average Mon-Thurs and Fri-Sun in two separate columns. I want
the
average to exclude the zero's or blanks that have not been filled in yet,
so
on Monday, the equation would simply have Monday's information, but when
Tuesday and Wednesday are filled in, it would include them as well as part
of
the average.

thanks