The objective of our research is to support for solving mathematical exercise in the collaborative learning environment. To promote the exchange of more varied opinions toward the correct answer, it is necessary for the support system to offer a communication means, recognize the learning situation, and provide appropriate advice according to the learning situation. In mathematical exercises, it is effective to propose a diagram to the learning group as form of advice. In this work, we construct a system that proposes supplementary figures in order to enable the group to derive the next step in a problem according to the current learning situation. In our system, a diagram which a learner draws is converted into an internal model. Then, supplementary figures according to the learning situation are generated by selecting and applying a rule for drawing diagrams that corresponds to the internal model. In this paper, we explain the overall framework for generating supplementary figures and show the results of an experiment to evaluate the system.