一、教材分析 “角的初步认识”是九年义务教育第三册第四单元的内容，它是在学生初步认识长方形、正方形和三角形的基础上教学的。教材从引导学生观察实物开始来认识日常生活中所看到的角，然后让学生自己动手折角、做活动角，进一步感知角，进而抽象出角的几何图形。 本节课 First, the textbook analysis “The initial understanding of angle” is the ninth unit of compulsory education Volume nine unit content, it is based on the initial understanding of students rectangular, square and triangle based on teaching. Teaching materials to guide students from the beginning to understand the real world to see the angle seen in daily life, and then let the students bend their corners, the corner of the activities, further perceived angle, and thus abstract the angular geometry. This lesson