This thesis which is about working with mathematics teaching has no effect/impact on performance and understanding of pupils. The study is intended to gain insight on working in mathematics education which has an impact on performance and understanding of students who are ethnically Swedish and foreign ethnic. In order to compare the ethnic Swedish and foreign students of ethnic understanding, I judged from their performance on the tests taken in year three. The qualitative approach permeated the work, both interviews and observations which were included in the survey. The qualitative study was chosen to get an understanding of how mathematics teaching is conducted in two different areas. The results of the investigation show that working in mathematics education is relevant to performance and understanding of students who are ethnically Swedish and foreign ethnic. In addition, it led to ethnically Swedish students having higher results than students who are ethnically non-resident in the comparison schools.