The purpose of this study was to look at how classes using the Khan Academy s mathematics Learning Program affect students math skills and task performance. The Khan Academy s Math Learning Program let learners study and evaluate Math departments by themselves according to their level. For this study, I chose 3 students with intellectual disabilities who were 4th grade of special school in Gyeonggi-do and had homogeneity in math performance and math task exection behavior. While conducting the Khan Academy math program, I looked at the achievement of mathematics math learning and the change of task performance behavior for 3 students. There were 25 interventions, as a result all students improved achievement of mathematics math learning and the participation rate in task performance behaviors increased. Based on these results, the proposals for practice and the limitations of research were presented.