在教学北师大版教材三年级下册第五单元“认识分数”一课时,我给学生设计了这样一道题:用分数表示图形阴影部分的面积。(见图1)当我把题目展示出来的时候,大部分学生认为应该用28表示;有一小部分学生不知道如何下手,不明白可用什么分数表示。我想深入了解学生的想法。师:同学们真是善于思考,谁还有不同的想法呢?经过了解,我发现认为用28表示的同学,他们觉得这个图形被分成了8份,阴影部分占 In the teaching of the North China Normal University textbook third grade unit fifth unit “cognitive score ” a class, I designed such a question for students: the fraction of the area that the shaded portion of the graph. (See Figure 1.) When I showed the topic, most students thought they should be expressed as 28; a small number of students did not know how to get started and did not understand what the available scores were. I want to know more about students’ ideas. Teacher: Students are really good at thinking, who have different ideas? After understanding, I found that the students indicated that 28, they think this figure is divided into 8, the shadow of the part of