The research in this experimental research with the objective. To develop computer-assisted instruction Mathematics Grade 3 and to find effective CAI developed. The tools used in this research include. CAI multimedia applications developed with Adobe flash cs5, Crazytalk Animator, Sony Vegas 10.0 and query management system Moodle lesson content experts and technical methods. The results showed that the CAI developed efficient and effective content in a technical way to a good level.