用简便方法计算. 0.8×6.2+3.8×0.81.25×32×2.5(0.25+25)×4(8.65+0.87)+1.35.
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解:(1)0.8×6.2+3.8×0.8,
=0.8×(6.2+3.8),
=0.8×10,
=8;
(2)1.25×32×2.5,
=1.25×8×4×2.5,
=(1.25×8)×(4×2.5),
=10×10,
=100;
(3)(0.25+25)×4,
=0.25×4+25×4,
=1+100,
=101;
(4)(8.65+0.87)+1.35,
=(8.65+1.35)+0.87,
=10+0.87,
=10.87.
解析分析:(1)(3)运用乘法分配律简算;(2)把32看做8×4,运用乘法结合律简算;(4)运用加法交换律与结合律简算.
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.