小学数学“义教”教材从一年级开始就出现一些常见的几何图形，以后逐步认识图形的特征，计算图形的周长、面积和体积。我们在实际教学中，发现学生在计算时，常常出现周长和面积不分，表面积与体积混淆，单位名称错写，圆锥体体积公式不完整等。这些错误，看似学生计算时精心 Elementary mathematics “Yi teaching” textbook from the first grade there are some common geometric graphics, and later gradually understand the characteristics of graphics, computing graphics perimeter, area and size. In the actual teaching, we found that when students calculate, they always appear perimeter and area, the surface area and volume confusion, the unit name is wrongly written, the cone volume formula is incomplete and so on. These errors appear to be meticulous when calculated by students