教材分析:《圆的周长》选自人教版六年制小学数学六年级上册“圆”的第二节。“圆的周长”概念教学是以长方形、正方形周长知识为认知基础的,是前面学习“圆的认识”的深化,是后面学习“圆的面积”等知识的基础,因此它起着承前启后的作用,是小学几何初步知识教学中的一项重要内容。 Textbook analysis: “Circumference of the circle” is selected from the second section of the PEP sixth grade mathematics version of the “Pinyin”. “Circle Perimeter ” concept teaching is based on knowledge of the rectangular, square perimeter knowledge, is the front learning “round understanding ” deepen, is to learn later “circle area ” and other knowledge Therefore, it plays an important role in the elementary teaching of elementary geometry.