差量法作为一种巧妙的解题方法，已被越来越多的人所应用，若能熟练掌握，不但可以提高解题的速度和准确率，而且能加强思维能力和解题技巧的务实训练。但是，在多轮教学中，笔者发现很多学生在被动接受这种方法并应用时，对该方法原理仍似是而非，仅从答案的准确中得到一种安 Differential method as an ingenious problem-solving method has been applied by more and more people. If you master it, you can not only improve the speed and accuracy of problem solving, but also strengthen the practical ability of thinking skills and problem-solving skills. training. However, in many rounds of teaching, the author found that many students passively accepted this method and applied it. The principle of this method is still plausible, and only an answer is obtained from the accuracy of the answer.