教完正反比例应用题后,我及时给学生组织练习课,把比例应用题中常见的三种基本形式通过一题多练和一题多变,有的改变已知条件,有的改变问题,有的同时改变已知条件和问题,让学生进行分组对比,从中探求比例应用题中常见的几种数量关系和解题规律。我的做法是把练习题分成三组,让学生有目的地进行练习。第一组:已知一组两个对应量和另一组所求问题 After teaching the application of positive and negative proportion, I organized the practice class to the students in a timely manner, changing the three basic forms of common application of the ratio through more than one question and one question, changing some known conditions and some changing problems, Some at the same time change the known conditions and problems for students to group comparison, from which to explore the proportion of common problems in the number of relations and problem-solving law. My approach is to divide the exercise into three groups, so that students can practice purposefully. First group: A set of two correspondences and one set of questions are known