用简便方法计算 写出简算过程(1)2.5×3.2×1.25(2)4.05-(2.05+527)(3)5.39+127+4.61+57(4)0.588×123+4×9.412+
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| 用简便方法计算,写出简算过程 (1)2.5×3.2×1.25 (2)4.05-(2.05+ (3)5.39+1 (4)0.588×1 |
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(1)2.5×3.2×1.25,
=(2.5×0.4)×(8×1.25),
=1×10,
=10;(2)4.05-(2.05+527),
=4.05-2.05-527,
=2-527,
=12227;(3)5.39+127+4.61+57,
=(5.39+4.61)+(127+57),
=10+2,
=12;(4)0.588×123+4×9.412+213×0.588,
=0.588×(123+213)+4×9.412,
=0.588×4+4×9.412,
=4×(0.588+9.412),
=4×10,
=40.
