小学三年级开始,学生开始接触面积等几何初步知识,学生主要是通过触摸、观察、比较、涂画等感知手段来建立面积这一几何概念。长方形面积的公式推导主要通过引导学生有序的摆放,了解水平方向与竖直方向可摆多少个面积单位,再计算出它们的乘积,算出一共可以摆满多少个面积单位,得知这个长方形的面积有多大。这一方法改变了求面积大小的 Beginning in the third grade of primary school, students begin to contact geometry and other initial knowledge of area. Students mainly establish the geometric concept of area by means of touching, observing, comparing, painting and other means of perception. Rectangular area of ​​the formula derived mainly through the guidance of students placed in order to understand the horizontal direction and the vertical direction can be placed how many units of area, and then calculate their product, calculate the total number of units can be filled with the unit, that the rectangle How big is the area This method has changed the size of the area