题目内容
6.5-(1.6÷5-0.3)
7.2-2.7÷15-0.82
×31-1÷![数学公式](http://thumb.1010pic.com/pic5/latex/597.png)
![数学公式](http://thumb.1010pic.com/pic5/latex/281912.png)
解:
(1)6.5-(1.6÷5-0.3),
=6.5-(0.32-0.3),
=6.5-0.02,
=6.48;
(2)7.2-2.7÷15-0.82,
=7.2-0.18-0.82,
=7.2-(0.18+0.82),
=7.2-1,
=6.2;
(3)
×31-1÷
,
=
-
,
=
;
(4)
,
=
,
=
,
=2.
分析:(1)先算除法,再算小括号里面的减法,最后算括号外面的减法;
(2)先算除法,再根据连减的性质进行计算;
(3)先算乘法和除法,再算减法;
(4)先算减法,再算乘法,最后算除法.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
(1)6.5-(1.6÷5-0.3),
=6.5-(0.32-0.3),
=6.5-0.02,
=6.48;
(2)7.2-2.7÷15-0.82,
=7.2-0.18-0.82,
=7.2-(0.18+0.82),
=7.2-1,
=6.2;
(3)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
=
![](http://thumb.1010pic.com/pic5/latex/324177.png)
![](http://thumb.1010pic.com/pic5/latex/137.png)
=
![](http://thumb.1010pic.com/pic5/latex/543640.png)
(4)
![](http://thumb.1010pic.com/pic5/latex/281912.png)
=
![](http://thumb.1010pic.com/pic5/latex/543641.png)
=
![](http://thumb.1010pic.com/pic5/latex/221654.png)
=2.
分析:(1)先算除法,再算小括号里面的减法,最后算括号外面的减法;
(2)先算除法,再根据连减的性质进行计算;
(3)先算乘法和除法,再算减法;
(4)先算减法,再算乘法,最后算除法.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
![](http://thumb2018.1010pic.com/images/loading.gif)
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