Points out of a maximum. The teacher is supposed to decide in advance how much points a test will be worth (5, 10, 20 and 25 being common options, but I've also had tests where I scored 17,26/27) and then decides how much points a question will be worth. You need to get half of the maximum or more for a passing grade.

That's in high school. In university everything is scored out of a maximum of 20 points.