学生在数学学习、解决问题的思维活动中,常习惯于正向思维,而忽视逆向思维的运用.然而数学知识本身充满着正反两个方向的转化,如运算与逆运算、全集与其补集、映射与逆映射、函数与反函数、相等与不相等、判定定理与性质定理、互斥事件的概率等.为了优化学生思维的各种品质、丰 Students often accustomed to positive thinking and neglect the use of reverse thinking in mathematics learning and problem-solving thinking activities.But mathematical knowledge itself is full of positive and negative transformations, such as computing and inverse computing, , Mapping and inverse mapping, function and inverse function, equality and inequality, judgment theorem and property theorem, the probability of mutually exclusive events, etc. In order to optimize the various qualities of students’ thinking, Feng