This case study focuses on teachers' actions during problem-solving lessons. The aim of this study was to find out how teachers guide students during mathematics problem-solving lessons: What kinds of questions do teachers ask? How do students arrive at solutions to problems? The dataset contained videotaped fourthgrade math lessons in which students solved a mathematical problem. The research reveals that teachers can guide students in numerous ways and possibly in ways that prevent students from searching for their own solution strategies. For this reason, problem-solving exercises alone are not sufficient for teaching problem solving for students, teachers must also be instructed in how to properly guide students. In the conclusion section, we discuss the types of questions that enable teachers to promote active learning in students, which should be the goal of instruction according to the constructive learning theory.