构建主义学说提出，数学的学习活动是一个以学生已有的知识经验为基础的主动建构过程。教师应该创设问题情境，引发认知冲突，让学生在参与实践中经历知识的生成和展开过程，产生复杂的情感体验，完成有意义建构。问题情境是促进学生自主探索的助推器，是意义建构过程的指路灯? The doctrine of constructivism suggests that the learning activity of mathematics is an active construction process based on the students' existing knowledge and experience. Teachers should create problem situations, trigger cognitive conflicts, enable students to experience knowledge in the practice of the formation and development process, resulting in complex emotional experience, the completion of meaningful construction. Problem situation is to promote students to explore their own booster is the process of construction of the meaning of the light?