This paper reports on teachers' perceptions of students learning as part of a project examining teacher practice and student learning when using "ScratchMaths" in their classroom programmes. The project used design-based methodology, incorporating video-recorded classroom excerpts; teacher interviews; and teacher analysis and review of their practice. The teachers identified the students' problem solving, using unplugged activities, and collaborating using explicit mathematical and coding language as ways to facilitate mathematical thinking. They also recognised that their practice became more faciliatory, with their understanding of coding developing through learning with their students.