Much research about classrooms has focused on what teachers do and their reflections about critical events in their lessons. Comparatively rare are studies that look at how students react to the many incidents and activities that take place during lessons. Students’ perceptions about lesson events form an important but often neglected source of data that can be used to understand the impacts of teaching on learning. This paper reports on some findings of the feelings and thinking of mathematically weak students during mathematics lessons. Four teachers, two from primary (P4) and two from secondary (S1) schools, taught a series of four to six lessons that covered a topic in their scheme of work. During each lesson, the teachers stopped the lesson after some time and administered to their students a one-page in-class reflection checklist about that segment of the lesson. At the same time, the teacher completed a similar reflection checklist from her perspective. This in-class reflection asked students about the purpose and importance of that segment of the lesson, their feelings, and what they were doing. The teachers were able to complete two in-class reflections in most lessons. At the end of the lesson, two target students and the teacher were interviewed about these reflections. The quantitative and qualitative data were analyzed to discover similarities and differences in teacher and student perceptions and patterns of responses intra- and inter-lessons. A practical implication is that the teacher can use this simple in-class reflection checklist to obtain information about student responses to the lesson to guide planning of subsequent lessons.