It is important to consider by learner itself. Therefore, we think that it is necessary to improve the capability for solving a problem without supports by the teacher or the tutoring system. In order to offer such learning environment, we proposed learning form. Our learning form provides the learning environment that learner itself finds a mistake personally and specifies mistaken act of learning in the process of repeating trial and error. And we proposed a learning support system for making the mutual conversion among Infix Notation, Binary Tree and Reverse Polish Notation. We experimented for investigating behavior of learners in learning and getting the knowledge for effective support strategy in order to support learning. As a result of the experiment, we found that there is the pattern making learners a mistake. We describe the procedures for constructing our learning support system and the learning support strategy by utilizing the pattern making learners a mistake.