怎样简便就怎样算????
7.8×101????????????????÷×64-1???????????×[-(-)]×0.53+75%×1.47???????
25×3.2×1.25???????????÷.
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解:
(1)7.8×101,
=7.8×(100+1),
=7.8×100+7.8×1,
=780+7.8,
=787.8;
(2)÷×64-1,
=×64-1,
=41-1,
=40;
(3)×[-(-)],
=×[-+],
=×[1-],
=×,
=;
(4)×0.53+75%×1.47,
=0.75×0.53+0.75×1.47,
=0.75×(0.53+1.47),
=0.75×2,
=1.5;
(5)25×3.2×1.25,
=25×(4×0.8)×1.25,
=(25×4)×(0.8×1.25),
=100×1,
=100;
(6)÷,
=(30+)×,
=30×+×,
=28+,
=28.
解析分析:(1)根据乘法分配律进行简算;
(2)先算除法,再算乘法,最后算减法;
(3)根据连减的性质,算中括号里面的,最后算乘法;
(4)根据乘法分配律进行简算;
(5)根据乘法交换律和结合律进行简算;
(6)根据乘法分配律进行简算.
点评:完成本题要注意分析算式中数据,运用合适的简便方法计算.