27分之28乘19-27分之19 简便算法

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原式=28/灶渗慎27*19-19/隐敬27
=19/27*28-19/喊悉27
=19/27*（28-1）
=19/27*27
=19

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28/27*19-19/27
=19/27(28-1)
=19/27*27
=19

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19

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