学习“用分数表示可能性的大小”之前,学生对“可能性的大小”这一知识并不陌生,且已掌握了怎样用语言来表述可能性的大小,但怎样用分数表示可能性的大小及怎样灵活运用分数表示可能性的大小来设计与判断一些游戏规则的公平性较为抽象,需要教师的正确引导和巧妙设计练习方能见到成效。基于这些问题,我打破教材中例题及练习的安排,层层深入地组织教学,化解了学生认识上的难点。一、游戏导入,趣味横生课前为了活跃课堂氛围,我先让学生同桌之间开展“石头、剪刀、布”的游戏,比一比谁赢的次数多,以此调动学生学习的积极性。然后我让赢得次数少的学生说一说这个游戏是否公平,自己获胜的可能性有多大。这样激活了学生 Before learning how to use fractional size, students are familiar with the possibility of size, and have mastered how to express the size of a possibility in words, but how to use a fraction The possibility of the size and how to use the score to indicate the possibility of the size of the design and determine the fairness of some rules of the game is more abstract and requires teachers to guide the correct guidance and ingenious design practice to be effective. Based on these problems, I break the teaching examples and practice arrangements, layers of in-depth organization of teaching, to resolve the difficulties of understanding students. First, the game is imported, interesting After class In order to active classroom atmosphere, I first allow students to carry out “stone, scissors, cloth ” between the same table, more than the number of winners in order to mobilize the students to learn Positivity. Then I asked students who won less to say how fair the game was and how likely they were to win. This activates the student