Implementation of Lesson Study in Undergraduate to Improve Mathematics Communication Ability

The purpose of this research is exploratory research by applying Lesson Study, which consists of three stages planning (Plan), implementation (Do), Objectives, and reflection (See). Subjects in this study are prospective teachers Teachers Faculty of Teacher Training and Education Dehasen University in Statistics courses amounting to 31 people. Data collection was done using observation sheets, test sheets, and documentation. The data were obtained from the observation sheet in the lesson study activity and the test sheets were analyzed descriptively. The results showed that the implementation of Lesson Study can improve students& #039, mathematical communication ability. This is seen from the average value of tests in Cycle I, which is 69.83 and Cycle II is 84.84.