German school system

I do not profess to being an expert, but having 2 kids in German schools, we have learnt a few things about German schools. The school system varies from state to state, so the following is about Baden Wüttemburg.
Kids start school in Germany at six or seven years old. But many German parents wait as ate as possible before the kids start school. The kids then go into Grundschule. The maximum number of kids in a class is 31, so the number of classes in each year depend on the number of kids entering. This means the class sizes also vary.

The kids spend 4 years in the Grundschule before moving to the next school. Traditionally there were 3 types of school, Gymnasium, Realschule and Hauptschule. Gynamisium is the equivalent of Grammer schools in England, and the kids are expected to go to university when they finish. The teaching is different, as the kids are expected to think for theseelves more.
Realschule is less a midde school. There is a more vocational element to the teaching, and the kids are more but the kids can go to university if they do an extra 2 years to do the Abscluss. Reaschule is less academic and is vocational based. Kids who go here are unable to go to university. Because may Hauptshcule have a bad reputation, there has been in the last few years a growth of a new school type Werkrealschule, which is between Real and Hauptschule.

The decision which school a child goes to after Grundschule is based on a teacher recommendation. All the work and tests in the 3 and 4 th years are marked. 1 th best, 6 the worst. The average for German and Maths is used to determine which school, the other subjects do not count. To go to Gymnasium the kid should have a 2.5 or higher average. Realschule 2.5 to 3.5 and Realschule below 3.5. If you disagree with the teacher recommendation, there is appeal prcoess where the kids are tested by the school.