在较复杂的应用题、数学竞赛题及智力趣味题中、当遇到题中的某些条件前行发生变化时,学生往往感到束手无策。对这类题目,如果采取“变中抓定”的思路,在数量关系的分析中,集中全力抓住“变中不变”的量作为突破口、问题就可迎刃而解。例1某工厂原有工人240人,其中女工占37.5％;后来又招来几个女工,这时女工占全厂工 In the more complex questions of application, mathematics competitions and intellectual interests, students often feel helpless when they encounter some problems in the questions. If we adopt the idea of ​​“change in grasping” on such topics and focus on the “constant change” in the analysis of the quantitative relationship as a breakthrough point, the problem can be solved easily. Example 1 There were 240 original workers in a factory, of which 37.5% were female workers. Later, several female workers were recruited, and at that time women workers accounted for the entire factory workers