Maybe something like

=LOOKUP(AVERAGE(IF(A1:A1000,A1:A100)),{0,50,60,70 ,80,90},{"F","E","D","C","B","A"})

as an array formula

HTH

Bob

"Param" wrote in message
...
Hi, I use below formula for marks(numbers)

For values in A1:A100

B1: =SUMIF(A1:A100,"0",A1:A100)/COUNTIF(A1:A100,"0")

OR

ARRAY FORMULA*
B1: =AVERAGE(IF(A1:A1000,A1:A100))

My Question: How to modify this formula for grade?