Expanding on Knowledge of Student Thinking through Mathematics Teachers’ Engagement in Lesson Study

The purpose of this study is to expand on knowledge of student thinking based on the mathematics teachers’ practices in a lesson study process designed for improving teachers’ knowledge of student thinking. The participants of this qualitative case study were three secondary mathematics teachers. The data were gathered from twenty-two hours lessons observations and field notes. By the data analysis, we got nine main components by constant comparison. The main components of knowledge of student thinking were (a) building on students’ mathematical ideas, (b) promoting students’ thinking of mathematics, (c) triggering and considering divergent thoughts, (d) engaging students in mathematical learning, (e) evaluating students’ understanding, (f) motivating students’ learning, (g) considering students’ misconceptions and errors, (h) considering students’ difficulties, and (i) estimating students’ possible ideas and approaches. This study supported the mathematics teachers in developing professional knowledge and also provided to elaborate the content of teachers’ knowledge of student thinking.