人教版小学数学五年级上册教材第35页有一找规律的习题引起了笔者的兴趣,原题要求学生用计算器计算前四题,试着写出后两题的积(为了下文研究方便,删去课本第一个等式3×0.7=2.1,但本文证明的规律同样适用于该等式):3.3×6.7=3.33×66.7=3.333×666.7= There is a law to find a regular basis for the author’s interest in the problem, the original question requires students to use the calculator to calculate the first four questions, try to write the last two questions of the product (for the following research convenience, Delete the first text of the textbook 3 × 0.7 = 2.1, but the law of proof of this article also applies to this equation): 3.3 × 6.7 = 3.33 × 66.7 = 3.333 × 666.7 =