分类是一种重要的思想方法,指的是要研究的问题包含多种可能情况,不能一概而论,必须按可能出现的所有情况分别讨论,得出各种情况下相应的结论,并判断其合理性.在列方程解答某些应用题时,你是否具有分类意识?下面介绍四例,希望能引起同学们的注意. Classification is an important way of thinking. It refers to the problem to be studied, which includes many possible situations. It can not be generalized. It must be discussed separately according to all situations that may arise, and the corresponding conclusions in various situations are obtained and its rationality is judged In the column equation to solve some of the questions, do you have a sense of classification? Here are four cases, hoping to arouse the students' attention.