一、提出问题有关和差关系的证明从等腰三角形、三角形、到四边形,圆,多次在各类几何证明习题中出现。笔者思考从课本的常规问题出发,把它设计成为开放性问题来给学生学习探究。启发学生对这道很平常的问题的一步步地深入思考和探究,可以使学生通过一道题,理解有关和差关系的一般证明方法和思想,在后续学习中打下分析证明这类问题的 I. Prove the problem The proof of the relationship between the isosceles and triangles, triangles, quadrilaterals, and circles has appeared in various types of geometrical proof exercises. The author thinks about proceeding from the general problems of textbooks and designing it as an open question for students to learn and explore. Inspire students to think and explore step by step on this very common problem. Students can pass a question and understand the general proof methods and ideas of relationship and difference. In the follow-up study, they can analyze and prove such problems.