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在现行统编小学数学课本中,“不好直接计算”的多边形,它的边与边之间的关系,通常是让学生进行视觉感知的。不仅是边和边之间的平行与垂直的位置关系未作交代,就连一些边的长度,也是要根据它的对边估计的。所以,在求“不好直接计算”的多边形面积之前,可以先进行一些操作训练。例如,用两脚规或直尺测量对边是否相等,以确定没有标注尺寸的一边的量数,从而作为对边是否相等的判断依据;用量角器测量多边形近似直角的角,以确
In the current compilation of elementary mathematics textbooks, the relationship between the “poorly-calculated” polygons and its edges is usually for students to visually perceive. Not only is the positional relationship between parallel and vertical edges and sides not given any account, even the length of some of the edges is also estimated from its opposite edges. Therefore, before we can find the area of polygons that we can not calculate directly, we can do some operational training first. For example, the use of two-legged or ruler to measure whether the edge is equal to determine the size of a side of the number of measurements, as the opposite side is equal to determine the basis;