题目内容
用简便方法计算
×
+
÷7
×
÷3
(
÷![数学公式](http://thumb.1010pic.com/pic5/latex/25550.png)
73×
+
×27.
解:(1)
×
+
÷7,
=
×
+
×
,
=
×
×2,
=
;
(2)
×
÷3,
=
×
×
,
=(
-
)×
,
=
×
,
=
;
(3)(
+
)÷
,
=(
+
)×
,
=
×
+
×
,
=1
+1,
=2
;
(4)73×
+
×27,
=(73+27)×
,
=100×
,
=60.
分析:(1)(2)把除法改为乘法,运用乘法分配律的逆运算简算;
(3)把除法改为乘法,运用乘法分配律简算;
(4)运用乘法分配律的逆运算简算.
点评:此题主要考查应用乘法分配律进行简便计算.
![](http://thumb.1010pic.com/pic5/latex/847.png)
![](http://thumb.1010pic.com/pic5/latex/335.png)
![](http://thumb.1010pic.com/pic5/latex/335.png)
=
![](http://thumb.1010pic.com/pic5/latex/847.png)
![](http://thumb.1010pic.com/pic5/latex/335.png)
![](http://thumb.1010pic.com/pic5/latex/335.png)
![](http://thumb.1010pic.com/pic5/latex/847.png)
=
![](http://thumb.1010pic.com/pic5/latex/335.png)
![](http://thumb.1010pic.com/pic5/latex/847.png)
=
![](http://thumb.1010pic.com/pic5/latex/48628.png)
(2)
![](http://thumb.1010pic.com/pic5/latex/2969.png)
![](http://thumb.1010pic.com/pic5/latex/182561.png)
=
![](http://thumb.1010pic.com/pic5/latex/2969.png)
![](http://thumb.1010pic.com/pic5/latex/182561.png)
![](http://thumb.1010pic.com/pic5/latex/8.png)
=(
![](http://thumb.1010pic.com/pic5/latex/2969.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/8.png)
=
![](http://thumb.1010pic.com/pic5/latex/2235.png)
![](http://thumb.1010pic.com/pic5/latex/8.png)
=
![](http://thumb.1010pic.com/pic5/latex/1302.png)
(3)(
![](http://thumb.1010pic.com/pic5/latex/1207.png)
![](http://thumb.1010pic.com/pic5/latex/25550.png)
![](http://thumb.1010pic.com/pic5/latex/25550.png)
=(
![](http://thumb.1010pic.com/pic5/latex/1207.png)
![](http://thumb.1010pic.com/pic5/latex/25550.png)
![](http://thumb.1010pic.com/pic5/latex/155571.png)
=
![](http://thumb.1010pic.com/pic5/latex/1207.png)
![](http://thumb.1010pic.com/pic5/latex/155571.png)
![](http://thumb.1010pic.com/pic5/latex/25550.png)
![](http://thumb.1010pic.com/pic5/latex/155571.png)
=1
![](http://thumb.1010pic.com/pic5/latex/848.png)
=2
![](http://thumb.1010pic.com/pic5/latex/848.png)
(4)73×
![](http://thumb.1010pic.com/pic5/latex/14.png)
![](http://thumb.1010pic.com/pic5/latex/14.png)
=(73+27)×
![](http://thumb.1010pic.com/pic5/latex/14.png)
=100×
![](http://thumb.1010pic.com/pic5/latex/14.png)
=60.
分析:(1)(2)把除法改为乘法,运用乘法分配律的逆运算简算;
(3)把除法改为乘法,运用乘法分配律简算;
(4)运用乘法分配律的逆运算简算.
点评:此题主要考查应用乘法分配律进行简便计算.
![](http://thumb2018.1010pic.com/images/loading.gif)
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