“镜面对称”是人教版小学数学第三册第五单元“观察物体”的第三课时,是前一课对称图形知识的延伸与拓展。本案例讲的是应用镜面对称知识来解决生活中镜面对称现象的一节练习课,教材在《课堂作业本》中(第41页)安排了这样一道练习题:你认为下面哪一张是镜子里看到的卡片?(如下 “Mirror Symmetry ” is the third lesson of the third unit of the third edition of the PEP Edition “Observation Object ”, which is the extension and expansion of symmetrical graphics knowledge in the previous lesson. This case is about applying mirror symmetry knowledge to solve the mirror of symmetry in life, a practice lesson, the textbook in “Classroom Homework” (p. 41) arranged an exercise: Which of the following you think the mirror See the card? (Below)