Verified answer

It could be on e of teh special grading systems. In my school for example, if a student hasn't complete a full class due to late entry for example, they get a 1 of 100. They get a 2 out of 100 for medical absence. So a Z could be something like that, a subsitute for normal grades because of some problem with grading or some other amtter.

There is no such thing as a grade "Z". There must be something fishy going on. Ask your parents to contact your school in order to sort this out.

Its prob a malfunction or typo

Chill out stpd

it's means your teacher is screwing with you. there's no such mark as a Z