一、教之惑——重“法”而轻“理”用“四舍五入”法求近似数是人教版新教材四年级上第13页例7的内容。其主要教学目标是:会用“四舍五入”法把一个大数省略万位或亿位后面的尾数,求出它的近似数;并在教学过程中,进一步培养学生的数感。从教材的编排意图与教学安排中,我们可以发现“四舍五入”求近似数以一种方法的形式呈现时,其主要教学策略是通过教师的讲授,结合具体数, First, the teaching of confusion - heavy “law ” and light “management ” with “rounding ” method for approximation is the fourth grade of the PEP textbook on page 13 of Example 7 content. The main teaching goal is: to use the “rounding” method to omit a large number of million or bits behind the mantissa, find its approximate number; and in the teaching process, to further develop the sense of the number of students. From the arrangement of teaching materials and teaching arrangements, we can find that when we round up the approximation to form a method, the main teaching strategy is through teacher’s teaching, combining concrete numbers,