题目内容
脱式计算,怎样算简便就怎样算
①600-480÷12
②9×![数学公式](http://thumb.1010pic.com/pic5/latex/425431.png)
÷![数学公式](http://thumb.1010pic.com/pic5/latex/113.png)
③(80-9.8)×0.6-2.12
④35×(1-
)÷![数学公式](http://thumb.1010pic.com/pic5/latex/35.png)
⑤3÷[
×(
-
)]
⑥(1-
)×(
+
)
解:①600-480÷12
=600-40,
=560;
②9×
-
÷![](http://thumb.1010pic.com/pic5/latex/113.png)
=9×
-
×9,
=(
-
)×9,
=
×9,
=
;
③(80-9.8)×0.6-2.12
=70.2×0.6-2.12,
=42.12-2.12,
=40;
④35×(1-
)÷![](http://thumb.1010pic.com/pic5/latex/35.png)
=35×
×
,
=49;
⑤3÷[
×(
-
)]
=3÷[
×
],
=3
,
=24;
⑥(1-
)×(
+
)
=
×
,
=
.
分析:①③④⑤⑥根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的;
②可根据乘法分配律计算.
点评:完成有关于分数的四则运算时要细心,注意通分约分.
=600-40,
=560;
②9×
![](http://thumb.1010pic.com/pic5/latex/2131.png)
![](http://thumb.1010pic.com/pic5/latex/7880.png)
![](http://thumb.1010pic.com/pic5/latex/113.png)
=9×
![](http://thumb.1010pic.com/pic5/latex/2131.png)
![](http://thumb.1010pic.com/pic5/latex/7880.png)
=(
![](http://thumb.1010pic.com/pic5/latex/2131.png)
![](http://thumb.1010pic.com/pic5/latex/7880.png)
=
![](http://thumb.1010pic.com/pic5/latex/36.png)
=
![](http://thumb.1010pic.com/pic5/latex/3086.png)
③(80-9.8)×0.6-2.12
=70.2×0.6-2.12,
=42.12-2.12,
=40;
④35×(1-
![](http://thumb.1010pic.com/pic5/latex/14.png)
![](http://thumb.1010pic.com/pic5/latex/35.png)
=35×
![](http://thumb.1010pic.com/pic5/latex/335.png)
![](http://thumb.1010pic.com/pic5/latex/4579.png)
=49;
⑤3÷[
![](http://thumb.1010pic.com/pic5/latex/9932.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/335.png)
=3÷[
![](http://thumb.1010pic.com/pic5/latex/9932.png)
![](http://thumb.1010pic.com/pic5/latex/5193.png)
=3
![](http://thumb.1010pic.com/pic5/latex/55360.png)
=24;
⑥(1-
![](http://thumb.1010pic.com/pic5/latex/6232.png)
![](http://thumb.1010pic.com/pic5/latex/6.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
=
![](http://thumb.1010pic.com/pic5/latex/6233.png)
![](http://thumb.1010pic.com/pic5/latex/1209.png)
=
![](http://thumb.1010pic.com/pic5/latex/96.png)
分析:①③④⑤⑥根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的;
②可根据乘法分配律计算.
点评:完成有关于分数的四则运算时要细心,注意通分约分.
![](http://thumb2018.1010pic.com/images/loading.gif)
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