能简算的要简算 5.7×1.4+1.4×4.39.05-3.86-3.146.84×10.1 87×2.5+8.7×75.
网友回答
解:(1)5.7×1.4+1.4×4.3,
=(5.7+4.3)×1.4,
=10×1.4,
=14;
(2)9.05-3.86-3.14,
=9.05-(3.86+3.14),
=9.05-7,
=2.05;
(3)6.84×10.1,
=6.84×(10+0.1),
=6.84×10+0.684,
=68.4+0.684,
=69.084;
(4)87×2.5+8.7×75,
=8.7×25+8.7×75,
=8.7×(25+75),
=8.7×100,
=870.
解析分析:(1)运用乘法分配律简算;(2)运用减法的性质简算;(3)把10.1看作10+0.1,运用乘法分配律简算;(4)根据数字特点,原式变为8.7×25+8.7×75,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.