The aim of this paper is to investigate and analyze practices in multilingual classrooms of mathematics in a compulsory school in Sweden where immigrant students have been known to succeed. The school is situated in a suburban and segregated area outside a major city where pupils come from mainly limited socio-economic backgrounds. The rate of second language learners are 70% of all pupils in this school.By using ethnographic methods, mainly interviews and participant observation, data was collected in four mathematics classrooms which corresponded to consecutive ages of education. The data include field notes and observation of artifacts in the environment as well as interviews and informal conversations with teachers and school leadership. Information from the school website, the authority in charge of quality in Swedish schools (Skolverket) and the municipality were also used.The analysis is based on a socio-political viewpoint that power is relational and reflected within schools.