Implementation of Lesson Study in Teaching Mathematics in Region 3, Cluster XI South Palu

This research is a descriptive study with qualitative approach, which aims to describe the application of Lesson Study in mathematics learning teachers and students Region 3 Cluster XI Palu Selatan. effectively applied mathematics. can be proven from results interviews explain that lesson understood by most who are members area South Palu. In addition, obtained activity plan plans, media used learning, modules, observation sheets. activities carried out there three important activities, namely teacher carrying mixed arithmetic operations, observers observing learning. listening activity, model starts discussion conveying his impressions, experiences, opinions about implementation he has out.