题目内容
能用简便方法的用简便方法计算.
×80%+
×
6×
+75%×3+
.
解:(1)
×80%+
×
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(2)6×
+75%×3+
,
=6×
+
×3+
,
=(6+3+1)×
,
=10×
,
=
.
分析:(1)把80%化成分数是
,再根据乘法分配律进行简算即可;
(2)把75%化成分数是
,再根据乘法分配律进行简算即可.
点评:把不同的数化成统一的数,再选择合适的运算定律进行简算即可.
![](http://thumb.1010pic.com/pic5/latex/1154.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/1154.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/1154.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/602.png)
=
![](http://thumb.1010pic.com/pic5/latex/602.png)
(2)6×
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
=6×
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
=(6+3+1)×
![](http://thumb.1010pic.com/pic5/latex/365.png)
=10×
![](http://thumb.1010pic.com/pic5/latex/365.png)
=
![](http://thumb.1010pic.com/pic5/latex/1047.png)
分析:(1)把80%化成分数是
![](http://thumb.1010pic.com/pic5/latex/602.png)
(2)把75%化成分数是
![](http://thumb.1010pic.com/pic5/latex/365.png)
点评:把不同的数化成统一的数,再选择合适的运算定律进行简算即可.
![](http://thumb2018.1010pic.com/images/loading.gif)
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