题目内容
简便运算.
25×125×32 | 75×2.5+25×3.6 | 72×(![]() ![]() | ![]() ![]() |
解:(1)25×125×32,
=25×125×8×4,
=(25×4)×(125×8),
=100×1000,
=100000;
(2)75×2.5+25×3.6,
=75×2.5+2.5×36,
=(75+36)×2.5,
=111×2.5,
=277.5;
(3)72×(
+
),
=72×
+72×
,
=27+16,
=43;
(4)
×
×16×8,
=(
×16)×(
×8),
=5×3,
=15.
分析:(1)把32化成8×4,再运用乘法的交换律、结合律进行简算,
(2)运用乘法的分配律进行简算,
(3)运用乘法的分配律进行简算,
(4)运用乘法的交换律、结合律进行简算.
点评:此题运用乘法的运算定律进行简算即可.
=25×125×8×4,
=(25×4)×(125×8),
=100×1000,
=100000;
(2)75×2.5+25×3.6,
=75×2.5+2.5×36,
=(75+36)×2.5,
=111×2.5,
=277.5;
(3)72×(
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/3982.png)
=72×
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/3982.png)
=27+16,
=43;
(4)
![](http://thumb.1010pic.com/pic5/latex/2520.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
=(
![](http://thumb.1010pic.com/pic5/latex/2520.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
=5×3,
=15.
分析:(1)把32化成8×4,再运用乘法的交换律、结合律进行简算,
(2)运用乘法的分配律进行简算,
(3)运用乘法的分配律进行简算,
(4)运用乘法的交换律、结合律进行简算.
点评:此题运用乘法的运算定律进行简算即可.
![](http://thumb2018.1010pic.com/images/loading.gif)
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