Now in their second year in a unified Berlin school system, principals and teachers, especially those from the east, have done a lot of adapting - and the process is not over yet.
"The colleagues in east Berlin had a very heavy school year last year, and they coped very well," says Sigrid Gonschior, an education officer in the city schools department. "They had new books, new conditions, a completely new system."
They also had job security: Although east Berlin had more teachers than were needed, the city government promised not to lay off any of them.
Under the old East German system, all pupils attended "polytechnical high school" until age 16. Only 10 to 20 percent went on for two more years to prepare for the Abitur, the exam that qualifies students for a university. Now east Germans can send their children to western-style Gymnasien to prepare for university.
"The teaching level is not as high as we would have expected," says Ms. Gonschior about schools in the former eastern zone. "They were making the right distinctions among the pupils [regarding grading], but the overall level was low.
In the east, the system was that the teachers would talk, and the students took notes. In the west, the process involved discussion, the pupils asking questions and getting answers."
That has changed now. City authorities have tried to help schools make themselves more attractive to parents, who can choose their children's schools. The city has also fostered contacts between individual teachers, principals, schools, and even districts and their counterparts in the other sector. "There's so much that they can learn from each other," says Gonschior.