题目内容
= | = | = | = |
= | 99×0.25+0.25= | = | 7.2÷100-0.72÷10= |
= | = |
解:(1),
=1,
=;
(2),
=0.875-0.75,
=0.125;
(3),
=×,
=;
(4),
=×8+×8,
=7+6,
=13;
(5),
=(5+4)+3.42,
=10+3.42,
=13.42;
(6)99×0.25+0.25,
=(99+1)×0.25,
=100×0.25,
=25;
(7),
=5.73+(1-1),
=5.73+0,
=5.73;
(8)7.2÷100-0.72÷10,
=0.072-0.072,
=0;
(9),
=()×,
=1×,
=;
(10),
=4.85-(+3),
=4.85-4,
=0.85.
分析:前两题都化成相同的形式的数再计算;(4)(6)(9)用乘法分配律简算;(5)(7)运用加法结合律简算;(10)利用减去两个数等于减去这两个数的和简算;其余题目按照运算法则直接运算.
点评:运算定律是常用的简便运算的方法,记住这些运算定律并灵活运用.
=1,
=;
(2),
=0.875-0.75,
=0.125;
(3),
=×,
=;
(4),
=×8+×8,
=7+6,
=13;
(5),
=(5+4)+3.42,
=10+3.42,
=13.42;
(6)99×0.25+0.25,
=(99+1)×0.25,
=100×0.25,
=25;
(7),
=5.73+(1-1),
=5.73+0,
=5.73;
(8)7.2÷100-0.72÷10,
=0.072-0.072,
=0;
(9),
=()×,
=1×,
=;
(10),
=4.85-(+3),
=4.85-4,
=0.85.
分析:前两题都化成相同的形式的数再计算;(4)(6)(9)用乘法分配律简算;(5)(7)运用加法结合律简算;(10)利用减去两个数等于减去这两个数的和简算;其余题目按照运算法则直接运算.
点评:运算定律是常用的简便运算的方法,记住这些运算定律并灵活运用.
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