教学内容义务教育课程标准实验教科书四年级下册117页《数学广角》例1、例2。片段一出示课件。(伴着钟的声音)师:上课的钟声再次响起,它将带我们去一个几何知识的 Teaching content The compulsory education curriculum standard experiment textbook The fourth grade of next page 117 “mathematical wide-angle” Example 1, Example 2. Fragment one to produce courseware. (Accompanied by the sound of bell) Teacher: The bell of class rang again, it will take us to a geometric knowledge