能简算的要简算.(-×)÷(-+)÷7.28÷0.8÷12.51.28×2.37-2.8×0.2370.65×14+87×65%-.

发布时间:2020-07-31 00:01:21

能简算的要简算.
(-×)÷
(-+)÷
7.28÷0.8÷12.5
1.28×2.37-2.8×0.237
0.65×14+87×65%-.

网友回答

解:(1)(-×)÷,
=[(1-)×]×5,
=××5,
=;

(2)(-+)÷,
=×24,
=8;

(3)7.28÷0.8÷12.5,
=7.28÷(0.8×12.5),
=7.28÷10,
=0.728;

(4)1.28×2.37-2.8×0.237,
=1.28×2.37-0.28×2.37,
=(1.28-0.28)×2.37,
=1×2.37,
=2.37;

(5)0.65×14+87×65%-,
=0.65×14+87×0.65-0.65,
=0.65×(14+87-1),
=0.65×100,
=65.

解析分析:(1)括号内运用乘法分配律简算,然后再算括号外的;(2)括号内进行通分计算,然后再算括号外的,把除法改为乘法计算;(3)运用除法的性质简算;(4)根据数字特点,把原式变为1.28×2.37-0.28×2.37,运用乘法分配律简算;(5)把百分数和分数转化为小数0.65,运用乘法分配律简算.

点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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