教材解读:把分数化成小数,基本方法是用分子除以分母,既然是除法,一定会有除尽和除不尽的情况。而分数化成小数是为第四单元学习分数、小数加减法的口算、笔算打下基础,同时又与第二单元有一定的联系。因此,本课的重点是让学生理解并掌握这个规律,并能利用这个规律进行判断,难点是在推导过程中理解这个规律。新课伊始,教师可先出示一组分数,先让学生进行计算,然后进行分类,并引导学生大胆猜想能化成有限小数可能与什么有关,与这个 Interpretation of textbooks: the fractionalized into decimals, the basic method is to use the numerator divided by the denominator, since it is the division, there will be divisible and indefinable circumstances. The fractionalized into decimal for the fourth unit learning scores, decimal addition and subtraction of the mouth count, pen and write lay the foundation, at the same time with the second unit has some contact. Therefore, the focus of this lesson is to enable students to understand and master this law, and can use this rule to judge, the difficulty is in the process of derivation to understand this law. At the beginning of the new lesson, teachers can first produce a set of scores, let students calculate, and then classified, and guide students to bold guess what can be turned into a finite decimal, and this