在立体几何第二章多面体和旋转体的内容中,计算题比较多,很多联系实际的应用题属于近似计算题.在过去使用十年制高中数学课本时,对近似计算没有引起足够的重视,教学中混乱现象比较严重。我们与学生一起到一些中学去参加教育实习,在多面体 In the content of the polyhedron and rotating body in the second chapter of the solid geometry, there are many calculation problems, and many applications related to the actual problem belong to the approximate calculation problem. In the past, when the ten-year high school mathematics textbook was used, the approximate calculation did not attract enough attention. Chaos in teaching is more serious. We went to some secondary schools together with students to participate in educational practice in polyhedrons.