论文部分内容阅读
在小学数学教学中,解答工程问题往往假设全工程为“1”。譬如,数学课本第九册第55页例5:一项工程,由甲工程队修建,需要20天,由乙工程队修建,需要30天,两队合修需要多少天?所附解答,就是把全工程看作“1”,然后得1÷(1/20+1/30)=12(天)。如果题目里对全工程给了具体数量,应该怎样解答,算理是不是一样?运算结果是否一致?例如,把例5中的“一项工程”改为
In elementary mathematics teaching, engineering problems are often assumed to be “1” for all projects. For example, Mathematics Textbook, Volume 9, Page 55 Example 5: A project to be constructed by A Construction Team takes 20 days. It will take 30 days for the B Project team to build. How many days will it take for the two teams to work together? Think of the whole project as “1” and then 1 ÷ (1/20 + 1/30) = 12 (days). If the title of the whole project gave a specific number, how to answer it, the logic is not the same and the results are consistent? For example, in Example 5, “a project” to