We make a quantitative analysis of educational effects by the division of Mathematics of Academic Support Center using Decision Tree. A dependent variable is an examination score, and independent variables are frequencies of use of various learning methods in Academic Support Center. The Decision Tree shows which learning method influences the examination score, and shows to what extent the learning method does. It is observed that students who solve exercises that we have made tend to get higher scores in the examination of Differentiation than students who don′t. On the other hand, concerning the examination of Multiple Integration, it is observed that face-to-face personal assistance method is effective.