下面两题用简便方法计算 - 知识问答

下面两题用简便方法计算

1个回答

4/9×7/11+7/9×5/11
=4/9×7/11+5/9×7/11
=（4/9+5/9）×7/11
=1×7/11
=7/11
7/11×5/19+5/11×4/19
=7/11×5/19+4/11×5/19
=（7/11+4/11）×5/19
=1×5/19
=5/19

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