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人教社六年制小数十二册练习二第9题如下: 一种压路机的前轮直径是1.32米。前轮的周长是多少米?如果每分钟转6转,它每分前进多少米?(得数保留整米)笔者认为,此题后面取近似值说明语欠鲜明。理由是:“得数”和“整米”所指不明。是第一问中的周长,还是第二问中的路程呢?两者均具双重指向性,学生往往不得而知。结果,在学生作业中出现两种不同得数:①3.14×1.32=4.1448(米),4.1448×6=24.8688≈25(米);②3.14×1.32=4.1448≈4(米),4×6=24(米)。如何才能做到取
People teach the six-year system of decimal twelve practice nine two is as follows: a roller front wheel diameter is 1.32 meters. How many meters perimeter of the front wheel? If you turn 6 rpm, how many meters per cent forward? (The number of retained whole meter) I believe that the title behind the approximate description of less than clear. The reasons are: “the number” and “whole meter” refers to the unknown. Is the perimeter in the first question, or is it the second question in the journey? Both have a dual orientation and are often unknown to students. As a result, two different numbers of occurrences occurred in student work: ① 3.14 × 1.32 = 4.1448 (m), 4.1448 × 6 = 24.8688≈25 (m); ② 3.14 × 1.32 = 4.1448≈4 6 = 24 (meters). How can we do it?