The purpose of this study is to examine a theoretical framework for the interactions of learning in a small group setting of mathematical problem solving. Many researchers already have described the theoretical background for the small group settings in problem solving. However, most of the literatures merely have reported findings of achievement and rising of test scores. They ignored the observation of process taken during the small group work and have not determined how various psychological, social and academic effects are created. As results of the study, two types, mutual collaboration and asymmetric collaboration, of interactions are observed as the interactions of learning, which are conceived as the cores of authentic mathematical activities.