Abstract
This study aims to improve the mathematics learning outcomes of fifth grade students of SDN 1 Bagik Polak Barat for the 2021/2022 academic year through the application of the Team Assisted Individualizatio model. The type of research used is Classroom Action Research with 4 stages, namely, planning, implementation, observation and reflection. This research was conducted in 2 cycles, where each cycle consisted of 3 meetings. The subjects in this study were all fifth grade students of SDN 1 Bagik Polak Barat who had a K13 curriculum. The data collection techniques used in this study were observation of the activities of teachers and fifth grade students at SDN 1 Bagik Polak Barat, as well as learning outcomes tests in each cycle. Based on data analysis, the activities of teachers and students were in the active category in the first cycle and in the second cycle increased to very active. As well as classical completeness in the first cycle of 79.16%, an increase in the second cycle of 95.83% and has reached the predetermined success achievement. So it can be said that the application of the Team Assisted Individualization learning model can improve the mathematics learning outcomes of fifth graders at SDN 1 Bagik Polak Barat for the 2021/2022 academic year.