记得去年我给毕业班进行总复习,有一节课复习的是“正比例的意义”。课上,我让学生举一些成正比例的例子。当时,有一位叫刘金楠的学生举了这样一个例子:如果x-y=0,那么x和y成比例。他剐说完,我便问学生:刘金楠同学说,x-y=0,x和y成正比例,对吗?同学们几乎都说:不对。是呀,因为我跟同学们说过:凡是加减关系的数量都不成比例。于是,我又对刚才刘金楠同学所举的例子作了进一步的否定,然后,便示意刘金楠 I remember last year I gave a general review of the graduation class, a class reviewed is “proportional meaning.” In class, I asked the students to give some examples of proportionality. At that time, a student named Liu Jin-nan gave the following example: If x-y = 0, then x is proportional to y. When he finished, I asked the students: Liu Jinnan said: x-y = 0, x and y are in proportion. Almost all of them said: No. Yeah, because I told my classmates that there is a disproportionate amount of any addition or subtraction. So I made a further negative comment on the example just given by my classmate Liu Jin-nan. Then I indicated Liu Jinnan