人教版小学四年级上册第二单元“线与角”中的《角的度量》这部分知识是学生后面学习画角、角的分类的基础。《角的度量》数学概念多,(如中心点、零刻度线、内刻度线、外刻度线都是一些抽象的纯数学语言)知识盲点多,几乎没有旧知识作铺垫,操作程序复杂,尤其是对于动作不够协调的四年级学生来说几乎没有用量角器测量角的体验,小小的量角器虽然被学生拿在手中,但学生对它的认识是陌生的,一条条放射状的线,不同的刻度,会使学生找不到量角器上的 People’s Education PYP fourth grade on the second unit “line and angle ” in the “measurement of angle” This part of the knowledge is behind the students learn painting angle, corner classification basis. There are many math concepts such as center point, zero scale line, inner scale line and outer scale line, all of which are mathematical math concepts. There are many blind spots in knowledge, and there is almost no old knowledge to pave the way for complicated operation procedures, especially For the fourth grade students who lack coordination, there is almost no experience of using the protractor to measure the angle. Although the small protractor is held by the students, the students are unfamiliar with it, with radial lines and different scales , Will make students can not find the protractor