简便运算.
125×3.2×2.50.9+99×0.9.
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解:(1)(++)÷,
=(++)×18,
=×18+×18+×18,
=6+3+2,
=11;
(2)1.875÷2.5-×0.4,
=0.75-,
=0.75-0.15,
=0.6;
(3)125×3.2×2.5,
=125×8×0.4×2.5,
=(125×8)×(0.4×2.5),
=1000×1,
=1000;
(4)0.9+99×0.9,
=(1+99)×0.9,
=100×0.9,
=90.
解析分析:(1)把除法改为乘法,运用乘法分配律简算;(2)先算除法和乘法,再算减法;(3)把3.2看作8×0.4,运用乘法结合律简算;(4)运用乘法分配律简算.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.