The aim of this study is to contribute with knowledge of how teachers in the Swedish School Age Educare system [Fritidshem] can work to complement the teaching in elementary school. The study further seeks to highlight and contribute with new knowledge in terms of how teachers conduct Lesson Study (LS) in order to enhance children’s mathematical learning in two contexts, the elementary school (grade 2-3) and the Fritidshem (during the same grades).

The data is collected with audio recorded conversations between researcher and teachers in two different contexts (ie. the elementary school and the fritidshem) and five open question in a questionnaire to map the students’ knowledge in chosen subject.

The teachers found that cooperating with each other between the different contexts was beneficial. They felt that mapping the pupils' knowledge before and after a teaching situation helped them understand how to create a teaching situation that benefits their students’ learning. They also see the value of continued collaboration and implementation of the LS method throughout the school’s organization.

The originality of this case study stems from the fact that the elementary school and the leisure-time center cooperate through an agreed subject content. Despite their different missions, this cooperation is in accordance with the governing documents.