Here we have:
1 - you did not know anything at all, or you were caught copying/cheating
2
3
4
5 - you need this to pass the class, you fail without it
6 - you need this at some subjects to pass the class if you're at a special school (e.g.: Music theory in a music highschool)
7
8
9
10 - perfect
The year has 2 semesters. In each subject, you need "the number of hours of that subject per week" marks, exception for those subjects that are only once a week, where you need 2, so the number of classes per week + 1.
At the end of a semester, an average is made for each subject. At the end of the second semester, same. At the end of the year, an average is made on each subject between the average on the first semester and the one on the second semester.
If your average per year on any subject is less than 5 (or 6 in special subjects, as I mentioned above), you will have a really hard exam in the autumn. If you don't pass that, you repeat the class.
There are also some more important subjects, where an "exam" ("teza") is given at the end of each semester. In highschool (9-10), those are Mathematics, Romanian, English (or French, depending of school), and special subjects (Music History and Instrument for music, Physics and computer science for some highschools, etc). This count a little more than a normal mark to your average.
The average is done like this: if you have a 9 and a 10 in a semester, the average will be 10. But the yearly average is NOT rounded. I had 9.95 last year.
I find this system almost perfect.
