也教用“四舍五入”求近似数,耳边萦绕着同伴教了这节能课后的两个烦恼:一是学生对书上的“是‘舍’还是‘入’,要看省略的尾数部分的最高位上的数是小于5还是等于或大于5”这句话中的“省略尾数部分的最高位上的数”理解起来很是困难,一致认为这是学生认识上的盲点和学习难点。二是新知教学后学生在刚刚建构起并能找出万后面尾数的最高位时,书本上的“做一做”(如下图),随即又把孩子对“尾数 Also use the ”rounding“ to find the approximate number, my ears are haunted by peers taught this two lessons after the energy-saving problems: First, the students on the book ”is“ or ’into’, depending on the omission The number of the most significant digit in the mantissa part is less than 5 or equal to or greater than 5 ”The phrase“ omit the most significant digit in the mantissa part of the mantissa ”is difficult to understand, and is consistently considered to be the student’s knowledge Blind spots and learning difficulties. Second, the new knowledge of teaching students just to build up and can find out the highest mantissa in million, the book “do a do” (as shown below), then turn the child on the "mantissa