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)
=
=7+6,
=13;
(5)
=(5
=10+3.42,
=13.42;
(6)99×0.25+0.25,
=(99+1)×0.25,
=100×0.25,
=25;
(7)
=5.73+(1
=5.73+0,
=5.73;
(8)7.2÷100-0.72÷10,
=0.072-0.072,
=0;
(9)
=(
=1×
=
(10)
=4.85-(
=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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