This study contains three themes as follows concerning the state of mathematics education and the textbooks in east and west germany before unification and in unified germany. The first subject is the investigations of the organization of the school systems and of the syllabus of mathematics in east germany in those days. Second, we analyzed the process of preparation for integration before unification, the nature of integration policies and the convention for the unification. Finally, we compare and analyze the similarities and differences in east and west german mathematics textbooks for middle school students combining those in south and north Korea, and further we suggest tasks to be studied in future research.