当一个数学命题的结论较强亦难于解决时,我们常想到能否把它弱化或简化,先从较弱的经过简化的问题着手并取得经验,在这个基础上进一步加深、提高达到解题的目的.这种思考问题的方式就是递进思维.它的特点是先退而后进.著名数学家华罗庚指出;“善于‘退’,退到最原始而不失重要性的地方,是学好数学 When the conclusion of a mathematical proposition is strong and difficult to solve, we often think of whether it can be weakened or simplified. We start with the weaker simplified problem and gain experience. On this basis, we can further deepen and improve the problem. Purpose. This way of thinking about problems is progressive thinking. Its characteristic is to retreat first. The famous mathematician Hua Luogeng pointed out that "good at ’retreat’, retreat to the most original but important place, is to learn mathematics