The purpose of the study is to increase knowledge about how preschool teachers plan and implement mathematics teaching in preschool. We used qualitative method to answer the research question. We used semi structured interviews. The findings of the study show that preschool teachers perceive mathematics teaching as a wide area in preschool. They use different strategies in mathematics education including dividing children in small groups, using concrete materials and mathematics educations in play-based activities etc. The result of the study shows that the preschool teachers have different views on planning mathematics education. The preschool teachers reason that mathematics teaching takes place both spontaneously and planned. In other words, they argue that mathematics teaching should be a natural part of their everyday practices. According to the preschool teachers, they are following the Swedish national curriculum in their mathematics education.