The study was intended to develop a teaching and learning set of Team Assisted Individualized on the materials of integer arithmetic operation. The development processes were define, design, and develop. The subjects of the study were the fifth graders of Public Elementary School 2 Later. The data was collected from the expert validation, observation, questionnaire, and the students' achievement test. The study produced a teaching and learning set which included (1) lesson plan, (2) students' book, and (3) students' worksheet. The validator gave 3.6 for the teaching and learning set; 84.6% for the implementation of the teachers' activities; 86.4% for the implementation of the students' activities; 93.1% for the teachers' respond; 92.5% for the students' respond l and 19 out of 21 students who took the achievement test achieved 90.5% of the completeness
