题目内容
(2012?嘉兴模拟)比较下面两个积的大小:A=9.5876×1.23456,B=9.5875×1.23457,则A
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B.分析:可用两数作差的方法进行比较大小,在计算时,可将算式9.5876×1.23456可改写成9.5875×1.23456+0.0001×1.23456,将算式9.5875×1.23457改写成9.5875×1.23456+9.5875×0.00001,然后再根据乘法分配律进行计算比较简便,由A-B大于0,可知A>B.
解答:解:A-B
=9.5876×1.23456-9.5875×1.23457,
=9.5875×1.23456+0.0001×1.23456-(9.5875×1.23456+9.5875×0.00001),
=0.0001×1.23456-0.001×0.95875,
=0.0001×(1.23456-0.95875),
=0.0001×0.27581,
=0.000027581,
0.000027581>0,
所以:A>B.
故答案为:>.
=9.5876×1.23456-9.5875×1.23457,
=9.5875×1.23456+0.0001×1.23456-(9.5875×1.23456+9.5875×0.00001),
=0.0001×1.23456-0.001×0.95875,
=0.0001×(1.23456-0.95875),
=0.0001×0.27581,
=0.000027581,
0.000027581>0,
所以:A>B.
故答案为:>.
点评:解答此题的关键是将算式中的数字进行改写,然后再依据乘法分配律进行解答.
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