The purpose of this thesis is to analyze the common mistake of junior high school students in decimal division calculation, and to enhance the students' ability of division calculation by different cooperative learning. The research is a quasi-experimental design. The researcher put into practice in summer subsidiary course. According to teaching experimental results, there have been no significant difference in pre-test, post-test and density test. But cooperative learning can enhance division learning effectiveness and is contributive to density calculation. The students of TPS method felt more satisfied with the course as a whole.