题目内容
能简算的要简算
40%×+60%× | 20%×-20%× | ×35%+0.25×65% |
75%×125-75%×25 | (+)×45 | 15×40%+85×40% |
解:(1)40%×+60%×,
=(40%+60%)×,
=1×,
=;
(2)20%×-20%×,
=20%×(-),
=20%×1,
=0.2;
(3)×35%+0.25×65%,
=0.25×(35%+65%),
=0.25×1,
=0.25;
(4)75%×125-75%×25,
=75%×(125-25),
=0.75×100,
=75;
(5)(+)×45,
=×45+×45,
=30+27,
=57;
(6)15×40%+85×40%,
=(15+85)×0.4,
=100×0.4,
=40.
分析:这几个题目都可以运用乘法分配律简算.
点评:乘法分配律是最常用的简算方法,要熟记,并灵活运用.
=(40%+60%)×,
=1×,
=;
(2)20%×-20%×,
=20%×(-),
=20%×1,
=0.2;
(3)×35%+0.25×65%,
=0.25×(35%+65%),
=0.25×1,
=0.25;
(4)75%×125-75%×25,
=75%×(125-25),
=0.75×100,
=75;
(5)(+)×45,
=×45+×45,
=30+27,
=57;
(6)15×40%+85×40%,
=(15+85)×0.4,
=100×0.4,
=40.
分析:这几个题目都可以运用乘法分配律简算.
点评:乘法分配律是最常用的简算方法,要熟记,并灵活运用.
练习册系列答案
相关题目