题目内容
计算,能简算的要简算.
43×![]() | ![]() ![]() ![]() ![]() | 2-![]() ![]() ![]() |
![]() ![]() ![]() | ![]() ![]() | (0.75-![]() ![]() ![]() |
解:(1)43×
,
=(42+1)×
,
=42×
+1×
,
=9+
,
=9
,
(2)
×
+
÷
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(3)2-
÷
-
,
=2-
×
-
,
=2-
-
,
=2-(
+
),
=2-2,
=0;
(4)
+![](http://thumb.1010pic.com/pic5/latex/4458.png)
,
=
+
×
,
=
+
,
=
,
=1
;
(5)
÷
×0.64,
=
×
×0.64,
=1.2;
(6)(0.75-
)×(
+
),
=
×
,
=
.
分析:(1)把43化成(42+1)的形式,运用乘法分配律进行简算,
(2)把除以
化成乘以
,运用乘法的分配律进行计算,
(3)根据分数出的运算法则计算,
(4)先算除法,再做加法,
(5)运用分数的四则运算顺序计算,把除法化成乘法计算,
(6)先算括号里,再算乘法.
点评:考查了分数四则混合运算的顺序计算,能简算要简算.
![](http://thumb.1010pic.com/pic5/latex/157734.png)
=(42+1)×
![](http://thumb.1010pic.com/pic5/latex/157734.png)
=42×
![](http://thumb.1010pic.com/pic5/latex/157734.png)
![](http://thumb.1010pic.com/pic5/latex/157734.png)
=9+
![](http://thumb.1010pic.com/pic5/latex/157734.png)
=9
![](http://thumb.1010pic.com/pic5/latex/10524.png)
(2)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/4442.png)
![](http://thumb.1010pic.com/pic5/latex/2766.png)
![](http://thumb.1010pic.com/pic5/latex/1653.png)
=
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/4442.png)
![](http://thumb.1010pic.com/pic5/latex/2766.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/4442.png)
![](http://thumb.1010pic.com/pic5/latex/2766.png)
=
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/4458.png)
(3)2-
![](http://thumb.1010pic.com/pic5/latex/14169.png)
![](http://thumb.1010pic.com/pic5/latex/28310.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=2-
![](http://thumb.1010pic.com/pic5/latex/14169.png)
![](http://thumb.1010pic.com/pic5/latex/57564.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=2-
![](http://thumb.1010pic.com/pic5/latex/304.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=2-(
![](http://thumb.1010pic.com/pic5/latex/304.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=2-2,
=0;
(4)
![](http://thumb.1010pic.com/pic5/latex/729.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/217036.png)
=
![](http://thumb.1010pic.com/pic5/latex/729.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/7580.png)
=
![](http://thumb.1010pic.com/pic5/latex/729.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=
![](http://thumb.1010pic.com/pic5/latex/23630.png)
=1
![](http://thumb.1010pic.com/pic5/latex/4442.png)
(5)
![](http://thumb.1010pic.com/pic5/latex/9932.png)
![](http://thumb.1010pic.com/pic5/latex/2581.png)
=
![](http://thumb.1010pic.com/pic5/latex/9932.png)
![](http://thumb.1010pic.com/pic5/latex/31142.png)
=1.2;
(6)(0.75-
![](http://thumb.1010pic.com/pic5/latex/1302.png)
![](http://thumb.1010pic.com/pic5/latex/3982.png)
![](http://thumb.1010pic.com/pic5/latex/8.png)
=
![](http://thumb.1010pic.com/pic5/latex/2235.png)
![](http://thumb.1010pic.com/pic5/latex/4442.png)
=
![](http://thumb.1010pic.com/pic5/latex/2520.png)
分析:(1)把43化成(42+1)的形式,运用乘法分配律进行简算,
(2)把除以
![](http://thumb.1010pic.com/pic5/latex/1653.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
(3)根据分数出的运算法则计算,
(4)先算除法,再做加法,
(5)运用分数的四则运算顺序计算,把除法化成乘法计算,
(6)先算括号里,再算乘法.
点评:考查了分数四则混合运算的顺序计算,能简算要简算.
![](http://thumb2018.1010pic.com/images/loading.gif)
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