Try this array formula** :

=AVERAGE(BB1:INDEX(X1:BB1,LARGE(IF(X1:BB1<"",COLU MN(X1:BB1)-COLUMN(X1)+1),3)))

** array formulas need to be entered using the key combination of
CTRL,SHIFT,ENTER (not just ENTER). Hold down both the CTRL key and the SHIFT
key then hit ENTER.

It assumes there will *always* be at least 3 numbers to average.

--
Biff
Microsoft Excel MVP


"Preschool Mike" wrote in message
...
I'm having trouble coming up with a formula that only averages the last
three
grades in a range. The range is X:BB and the grades are as percentages
(e.g., 100%). Note: Some cells in the range may not have data in them, so
the formula needs to overlook them and only average the last three grades
entered.

All help is appreciated.

Thanks,
--
Mike Mast
Special Education Preschool Teacher