good day i should know this formula but for some reason i can't remember. need to average some cells but ignore the dreaded #div error

ex

A25 is 25
A50 is 30
A75 is #div/0!
A100 is 30

so i need to get the average of those but ignore the #div/0!

those cells are a result of an average of a range (a1:a25 etc) so the formula could also be in that range as long as the formula the get the overall average doesn't count in any 0's.