Data Analysis
For Qualitative Data Analysis, Video Analysis supported by Protocol was an opening of Video Tape based on teaching steps of Open Approach in order to see movement as well as speak-ing by teacher and students while the students were solving the open-ended problem. Then, they were deciphered into Protocol. The word “Protocol” referred to deciphering the behavior ob-taining from audio tape and video tape into narration including pictures and word describing the occurred gestures in classroom according to the teaching incidence by Open Approach by us-ing the word “Item” which referred to one’s behaviors includ-ing each one’s spoken language and gestures, writing, and body movement. The word “Episode” referred to the behavior groups expressed by the students during their Mathematical communi-cation, and used in analytical describing the students and teacher’s behaviors expressing in classroom by analyzing the students’ gestures under context of Lesson Study and Open Approach respectively through the steps of Open Approach and being based on data analysis unit as basic cycle of dyad feed-back, by adapting from Emori (2005) in order to consider the students’ gesture that it was a message sending or receiving by students while they were solving mathematical problem. So, the sent or received message might be either spoken words or ges-tures using in investigating the students’ common understand-ing whether they had.