Try this

=LOOKUP(AVERAGE(IF(NOT(ISERROR(A1:A5)),LOOKUP(A1:A 5,{"A","B","C","D","E"},{1,2,3,4,5}))),{1,2,3,4,5} ,{"A","B","C","D","E"})

It may or may not be right, depending upon the formula that generates the
original grade, it would be better to go back to that formula.

--
HTH

Bob

(there's no email, no snail mail, but somewhere should be gmail in my addy)

"Param" wrote in message
...
I have grades that (link from diferrent worksheets)
e.g.

A1: C
A2: A
A3: D
A4: #DIV/0! (because no input at that particular worksheet)
A5: #DIV/0! (because no input at that particular worksheet)

Formula I used as below:

ARRAY FORMULA*
A6: =AVERAGE(IF(A1:A50,A1:A5))

the return answer is #div/0!

how to modify this formula to cater for grades.