“三角形的认识”一课是苏教版小学数学四年级下册第三单元的教学内容。学生在一年级时对三角形已经有了一定的直观认识,在此基础上,教材引领学生对三角形进一步探究,从而对三角形的基本特征,三角形任意两边之和大于第三边进行深层理解。三角形三边之间的关系是本节课的 “Triangle awareness ” lesson is the teaching content of the fourth unit of the fourth grade of Sujiao version of elementary school mathematics. Students in the first grade of the triangle has been a certain degree of intuitive understanding, on this basis, the textbooks lead the students to further explore the triangle, so that the basic characteristics of the triangle, the triangle on both sides of the greater than the third and deeper understanding. The relationship between the three sides of the triangle is in this lesson