This paper reports on teachers’ perceptions of their students’ learning as part of a project examining the learning that took place when the students used ScratchMaths in their classroom programme. The project used design-based methodology, which incorporated video-recorded classroom excerpts, teacher interviews and teacher analysis and review of their practice. The teachers identified the students’ problem solving, use of unplugged activities and collaborating using explicit mathematical and coding language as ways to facilitate thinking. They also recognised that their own practice evolved into a more faciliatory role, while their understanding of coding processes grew through learning beside, and through, their students.