Application of Cooperative Learning to Improve the Understanding of Mathematical Concepts in Junior High School

The purpose of this study is to improve learning activities and understanding mathematical concepts by applying the Group Investigation of cooperative learning model in class VIII.6 SMP Negeri 4 Bengkulu City. This research was a Classroom Action Research. The instrument used was the student’s activity observation sheet and the student’s concept understanding test sheet. Improved learning activities can be done by: using props at each meeting, reminding students how to measure appropriately, distracting students' attention by provoking students’ ideas, and lazy group members will be designated as presenter groups. Increased student’ learning activities in the first cycle with an average of 21.5 (quite active), and the second cycle increased by an average of 28.75 (active). An increase in understanding of mathematical concepts can be done by: each student notes the important things presented by the presenter group, and is given practice questions at the end of each meeting. Increased students’ understanding of mathematical concepts seen from the average test results of students' understanding concepts in the first cycle that was 60.61 and in the second cycle increased to 76.62. The percentage of mastery learning classically in the first cycle was 39.39% and in the second cycle was 63.64%.