The purpose of a series of our studies is to examine the role of "self-referential-activity" on mathematical problem solving. The term "self-referential-activity" means solver's activities that he/she refers to his/her own solving processes or products during or after problem solving. In study (I), we proposed the theoretical framework for analyzing self-referential-activity. And, in study (II) and (III), we elaborated the variable "OG/NOG" and "M-SE/SE-C" respectively. In study (V), we discussed some possibilities of transition from unsuccessful situation to successful one or of keeping successful situataion in problem solving process. And, from this perspective we proposed some teacher's suggestions or comments that enable solver to move from unsuccessful situations to successful one or to keep successful situation. Furthermore, we assumed that such suggestions or comments do not always need to be general one and be oriented to current situation. In this article, we examined the assumption by exploring college students' problem solving processes. The task that subjects solved was called "Making-Square-Problem" which purpose was to construct a square from two given smaller squares (e.g.7cm and 3cm). The subjects were asked to solve the task and an interviewer gave some suggestions or comments that we proposed in previous study, and the problem-solving activities were analyzed from our theoretical framework. As a result, the suggestions or comments proposed in previous study were effective on improving solvers' problem solving activities or on keeping successful situation. And it is suggested that such suggestions or comments are effective not only at the phase until the end of problem solving but also at the stage after the end of problem solving.
