Tony,

=(SUM(B2:B6)-IF(COUNT(B2:B6)=5,MIN(B2:B6),0))/MIN(COUNT(B2:B6),4)

with test grades in B2:B6

HTH,
Bernie
MS Excel MVP


"Tony" wrote in message
...
I can't figure out a formula for the following problem:
Student A has the choice of taking 4 out of 5 possible test but if he took
all 5 then the lowest grade would be dropped??