The objectives to be achieved in this study are: to determine the increase in mathematics learning achievement in addition and reduction of use through Abakus media in Class I.B students of SD Negeri 45 Mataram Odd Semester 2019/2020 Academic Year. This type of research is Classroom Action Research  which is based on the main concept that action research consists of four components, namely: (1) Planning, (2) Action, (3) Observation and (4) Reflection, the four stages of the activity are called one problem solving cycle. The data analysis in this study used a comparative descriptive method. One of the mathematics learning media is Abakus. Abakus is a Mathematics learning medium that is used to explain the concept of the place value of a number, addition and subtraction operations. From the research results it is known that the student learning outcomes in cycle III are as expected. The class average has reached 84.61%, according to the success indicator, which is ≥ 85. Meanwhile, the percentage of student learning outcomes who score ≥ 80 reaches 93.94% in accordance with the success indicator, which is at least 85%. Thus it can be concluded that learning with Abakus media is effective for improving Mathematics learning achievement in addition and subtraction in grade I.B students of SD Negeri 45 Mataram.