小学数学三年级上册第八单元《可能性》(北师大版)教材中设计了一个重要的学习活动:让学生通过摸球活动体会随机事件发生的可能性大小。教学这一课时,我准备了5只黄球、5只白球和1只不透明的袋子。课上,我抽取两名同学到讲台前进行实验:甲摸球10次,每摸出一次要给大家展示一下球的颜色,再 Pupils of Mathematics in the third grade on the eighth unit “Possibilities” (Beijing Normal University Edition) teaching materials in the design of an important learning activities: Students through the touch ball activities experience the possibility of random events. When teaching this class, I prepared 5 yellow balls, 5 white balls and 1 opaque bag. During class, I took two classmates to the stage for experiments: A ball 10 times, every time to show everyone to show the ball color, and then