%0 Journal Article %T Boundaries of the Community of Teachers¡¯ Implementing Mathematics Textbooks with Lesson Study and Open Approach %A Chanika Senawongsa %A Maitree Inprasitha %A Anake Sudejamnong %J Creative Education %P 1999-2012 %@ 2151-4771 %D 2019 %I Scientific Research Publishing %R 10.4236/ce.2019.109146 %X This study aimed to analyze boundaries of the community of teachers¡¯ implementing the mathematics textbooks with Lesson Study and Open Approach. For this study, Mathematics textbooks were Japanese mathematics textbooks (Thai version), consisting of mathematics problems, flow of lesson, and students¡¯ mathematical ideas. The participants were 2 expert teachers who use the textbooks in the classroom using Lesson Study and Open Approach since 2013. The data were collected in 2017 school year by using interview andclassroom observation with video recording. The data were analyzed based on Wenger, McDermott, & Snyder (2002)¡¯s framework of community of practice. The results showed that the teachers practiced in 3 boundariesof the community: 1) within school¡ªevery week, they use the textbooks to design mathematical problems and anticipating students¡¯ ideas with their school team, then they teach the lesson and observe students¡¯ ideas in the classroom, and they reflect on students¡¯ ideas that occurred in their classroom, 2) across schools¡ªevery semester, they form team with teachers who work in different schools of the project to design/observe/reflect a classroom by using the textbooks