题目内容
用你喜欢的方法计算.
136×![]() | 2001×3.14+200.1×31.4+20.01×314 |
![]() ![]() ![]() ![]() | 333×334+999×222 |
1.25×17.6+36.1÷0.8+2.63×12.5 | ![]() ![]() ![]() |
解:(1)136×![](http://thumb.1010pic.com/pic5/latex/329497.png)
=(135+1)×
,
=135×
+1×
,
=2+
,
=2
;
(2)2001×3.14+200.1×31.4+20.01×314
=2001×3.14+2001×3.14+2001×3.14,
=2001×3.14×3,
=(2000+1)×9.42,
=2000×9.42+1×9.42,
=18840+9.42,
=18849.42;
(3)
-[(
+
)×
]
=
-[
×
],
=
-
,
=
;
(4)333×334+999×222
=333×334+333×(3×222),
=333×334+333×666,
=333×(334+666),
=333×1000,
=333000.
(5)1.25×17.6+36.1÷0.8+2.63×12.5
=1.25×17.6+36.1×1.25+26.3×1.25,
=(17.6+36.1+26.3)×1.25,
=80×1.25,
=100;
(6)
÷(
+2.5×
)
=1
÷(
+2),
=
÷
,
=
.
分析:(1)可将136拆分为135+1后,根据乘法分配律计算;
(2)可根据乘法算式的性质将题目中的乘法变为具有相同因数2001与3.14的算式后,再将2001拆分为2000+1进行计算;
(3)(6)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;
(4)可将999拆分为333×3后再根据乘法结合律、分配律计算;
(5)可将36.1÷0.8变为36.1×1.25后,将2.63×12.5变化26.3×1.25后再根据乘法分配律计算.
点评:完成本题要细心分析题目中数据的特点及内在联系,然后运用合适的方法进行计算.
![](http://thumb.1010pic.com/pic5/latex/329497.png)
=(135+1)×
![](http://thumb.1010pic.com/pic5/latex/329497.png)
=135×
![](http://thumb.1010pic.com/pic5/latex/329497.png)
![](http://thumb.1010pic.com/pic5/latex/329497.png)
=2+
![](http://thumb.1010pic.com/pic5/latex/329497.png)
=2
![](http://thumb.1010pic.com/pic5/latex/329497.png)
(2)2001×3.14+200.1×31.4+20.01×314
=2001×3.14+2001×3.14+2001×3.14,
=2001×3.14×3,
=(2000+1)×9.42,
=2000×9.42+1×9.42,
=18840+9.42,
=18849.42;
(3)
![](http://thumb.1010pic.com/pic5/latex/5192.png)
![](http://thumb.1010pic.com/pic5/latex/13.png)
![](http://thumb.1010pic.com/pic5/latex/14.png)
![](http://thumb.1010pic.com/pic5/latex/6232.png)
=
![](http://thumb.1010pic.com/pic5/latex/5192.png)
![](http://thumb.1010pic.com/pic5/latex/25378.png)
![](http://thumb.1010pic.com/pic5/latex/6232.png)
=
![](http://thumb.1010pic.com/pic5/latex/5192.png)
![](http://thumb.1010pic.com/pic5/latex/13.png)
=
![](http://thumb.1010pic.com/pic5/latex/112.png)
(4)333×334+999×222
=333×334+333×(3×222),
=333×334+333×666,
=333×(334+666),
=333×1000,
=333000.
(5)1.25×17.6+36.1÷0.8+2.63×12.5
=1.25×17.6+36.1×1.25+26.3×1.25,
=(17.6+36.1+26.3)×1.25,
=80×1.25,
=100;
(6)
![](http://thumb.1010pic.com/pic5/latex/60550.png)
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
=1
![](http://thumb.1010pic.com/pic5/latex/112.png)
![](http://thumb.1010pic.com/pic5/latex/96.png)
=
![](http://thumb.1010pic.com/pic5/latex/4491.png)
![](http://thumb.1010pic.com/pic5/latex/2321.png)
=
![](http://thumb.1010pic.com/pic5/latex/13.png)
分析:(1)可将136拆分为135+1后,根据乘法分配律计算;
(2)可根据乘法算式的性质将题目中的乘法变为具有相同因数2001与3.14的算式后,再将2001拆分为2000+1进行计算;
(3)(6)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;
(4)可将999拆分为333×3后再根据乘法结合律、分配律计算;
(5)可将36.1÷0.8变为36.1×1.25后,将2.63×12.5变化26.3×1.25后再根据乘法分配律计算.
点评:完成本题要细心分析题目中数据的特点及内在联系,然后运用合适的方法进行计算.
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目