There is a large body of literature on feedback, and different kinds of feedback are said to be more beneficial than others. The literature claims that in order to enhance performance, feedback must not focus on the person, but on the strengths and weaknesses of particular pieces of work, and the processes involved in improving. This makes substantial demands on teacher knowledge, in terms of subject knowledge, to make sense of what pupils say and to determine the appropriate next steps. This presentation draws on data from the LPS in Norway, on data of one teacher’s lessons (grade 8, 10 consecutive lessons), analysed through the lens of ‘feedback’. For this an ‘analysis tool’ was developed from the literature which identifies particular kinds of feedback and their relationship to each other. The different kinds of feedback this teacher provides are explored, how they play out in the classroom, and how the teacher and pupils account for it in after-lesson discussions. Feedback is particularly important in the Norwegian schooling system, as pupils are provided with a two-weekly timetable where they work at their own speed and level with the mathematics; feedback is vital in such an individualised system.