“化二为一”法初中考试和竞赛中多次出现,它体现了一种化归思想,是对学生能力要求的进一步提升,不少同学觉得其变化规律不易掌握.笔者根据这些题目的特征,得到了“化二为一”的四种常规方法,并加以推广. “The law is a ” law junior high school exams and competitions appear many times, it embodies a return to thinking, is to further enhance the ability of students, many students feel that the law of change is not easy to grasp.The author based on these topics The characteristics of the “two” is one of the four conventional methods, and to promote.