Implementation of Lesson Study in Mathematics Learning Based on Student Cognitive Style

The research on the implementation of the lessson study aims to obtain information on students' readiness in learning mathematics based on their cognitive style. There are two types of students', field dependent and field independent cognitive styles. The method of obtaining information on students' readiness in learning mathematics through this first lesson study phase is that the plan is an initial activity with the lesson study team to discuss various preparations which needed. The second stage is the process of observing during the lesson study process in the classroom, the main observation of observers at the lesson study is to emphasized when students have questions and answers between lecturers and students and when students discuss in groups. The last stage is seeing as a form of evaluation of conclusions through lecturer model expressions and various findings from all observers in order to improve and be analyzed by researchers. Information on student readiness in mathematics learning becomes a reference for lecturers' preparation in preparing the necessary tools, models or learning methods. Early preparation by the lecturer can support the peak achievement of students during learning.