This article examines teacher formulations in teacher-fronted whole class interactions. Using conversation analysis (CA), we have analysed topic talk between teachers and students (12-16 years old) in Norwegian classrooms. We have identified three sub-groups of teacher formulations-transforming, challenging, and summarising formulations. We show how teacher formulations in topic talk are an important part of teaching and that the formulations serve different and specialised functions in classroom interactions. Our main finding is that teachers use the formulations to establish a shared pedagogic focus, the learnable. This study contributes by providing knowledge on formulations as a pedagogical device and by accumulating knowledge about the practice of formulation in general.