题目内容
脱式计算.
(1)7.8÷[32×(1-
)+3.6
(2)[5-
+(
+2.25×
)]÷0.125.
解:(1)7.8÷[32×(1-
)+3.6],
=7.8÷[32×
+3.6],
=7.8÷[12+3.6],
=7.8÷15.6,
=0.5;
(2)[5-
+(
+2.25×
)]÷0.125,
=[5-
+(
+0.75)]÷0.125,
=[5-
+
]÷0.125,
=[
+
]÷0.125,
=
÷0.125,
=
.
分析:(1)先算小括号里的减法,再算中括号里的乘法,再算中括号里的加法,最后算括号外的除法,
(2)根据四则混合运算的顺序计算即可:先算乘除,再算加减,有括号先算括号里面的.
点评:考查了整数、小数、分数四则混合运算的顺序,注意有括号的运算方法.
![](http://thumb.1010pic.com/pic5/latex/5192.png)
=7.8÷[32×
![](http://thumb.1010pic.com/pic5/latex/597.png)
=7.8÷[12+3.6],
=7.8÷15.6,
=0.5;
(2)[5-
![](http://thumb.1010pic.com/pic5/latex/233923.png)
![](http://thumb.1010pic.com/pic5/latex/221237.png)
![](http://thumb.1010pic.com/pic5/latex/8.png)
=[5-
![](http://thumb.1010pic.com/pic5/latex/233923.png)
![](http://thumb.1010pic.com/pic5/latex/221237.png)
=[5-
![](http://thumb.1010pic.com/pic5/latex/233923.png)
![](http://thumb.1010pic.com/pic5/latex/42999.png)
=[
![](http://thumb.1010pic.com/pic5/latex/155.png)
![](http://thumb.1010pic.com/pic5/latex/42999.png)
=
![](http://thumb.1010pic.com/pic5/latex/58529.png)
=
![](http://thumb.1010pic.com/pic5/latex/94310.png)
分析:(1)先算小括号里的减法,再算中括号里的乘法,再算中括号里的加法,最后算括号外的除法,
(2)根据四则混合运算的顺序计算即可:先算乘除,再算加减,有括号先算括号里面的.
点评:考查了整数、小数、分数四则混合运算的顺序,注意有括号的运算方法.
![](http://thumb2018.1010pic.com/images/loading.gif)
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