“…Those studies cover: First, open ended problem implementation in developing mathematics communication (Kongthip, Inprasitha, Pattanajak, & Inprasitha, 2012;Rodriguez & Bonner, 2018;Sumaji, Sa'dijah, Susiswo, & Sisworo, 2020;Thinwiangthong, S, Inprasitha, M, & Loipha, S, 2012). The findings were: (1) Rodriguez & Bonner (2018) state the use of open ended problem could improve teacher's skill in asking questions and creating dialogue between teacher and student more productive and better, (2) Thinwiangthong, Inprasitha, & Loipha (2012) revealed that mathematics class adopting lesson and transparent approach, could improve mathematical communication, (3) Kongthip et al, (2012) explained that schools in lesson study context and transparent approach allowed the students to have greater learning opportunity based on their potencies, thinking skills, actions, and expressions, and (4) Sumaji et al, (2020) found that (1) mathematical communication of students for both in written and spoken was on first level. It was in solving limited open ended problem on several concepts and (2) mathematical communication of students for both written and spoken was on level two.…”