Uuuuh it depends if we are talking about university or school now. The school system is different in every country so I can just talk about Germany and even here it's not the same in all states
But in school you have oral tests, writtens tests an class exams, so your grade consists of several grades but how many depends on teacher and subject. (I had subjects where it was just 2 grades and others it were like 8)
In university you usually just have one exam at the end of each course and sometimes an assignment. Which is shit, because you usually write all exams in the same week, learning for that is no fun at all and writing 3 assignments at the same time isn't really fun too >.> But this also depends on the university and even your subject.
(Don't kill me if I threw around wrong words, I looked most of them up o.o")