题目内容
56×(![]() ![]() | (![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
解:(1)56×(
-
),
=56×
-56×
,
=24-21,
=3;
(2)9.75-3.42-5.58,
=9.75-(3.42+5.58),
=9.75-9,
=0.75;
(3)125×0.25×3.2,
=125×0.25×4×0.8,
=125×0.8×0.25×4,
=100×1,
=100;
(4)(
-
)×
,
=
×![](http://thumb.1010pic.com/pic5/latex/4458.png)
×
,
=![](http://thumb.1010pic.com/pic5/latex/7295.png)
=![](http://thumb.1010pic.com/pic5/latex/7295.png)
,
=
;
(5)
×
+
÷8
=
×
+
×
,
=
×(![](http://thumb.1010pic.com/pic5/latex/597.png)
),
=
×
,
=
;
(6)
+
×
,
=
×(3+
),
=
×
,
=
.
分析:(1)根据乘法的分配律作答;
(2)根据连续减去两个数,等于减去这两个数的和;
(3)将3.2拆成0.8和4的积,再根据乘法的交换律作答;
(4)、(5)、(6)根据乘法的分配律作答.
点评:解答此题的关键是,运用乘法的分配律及乘法的交换律,使计算简便.
![](http://thumb.1010pic.com/pic5/latex/1154.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
=56×
![](http://thumb.1010pic.com/pic5/latex/1154.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
=24-21,
=3;
(2)9.75-3.42-5.58,
=9.75-(3.42+5.58),
=9.75-9,
=0.75;
(3)125×0.25×3.2,
=125×0.25×4×0.8,
=125×0.8×0.25×4,
=100×1,
=100;
(4)(
![](http://thumb.1010pic.com/pic5/latex/14.png)
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/14.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/1603.png)
![](http://thumb.1010pic.com/pic5/latex/4458.png)
=
![](http://thumb.1010pic.com/pic5/latex/7295.png)
![](http://thumb.1010pic.com/pic5/latex/6508.png)
=
![](http://thumb.1010pic.com/pic5/latex/7295.png)
![](http://thumb.1010pic.com/pic5/latex/441064.png)
=
![](http://thumb.1010pic.com/pic5/latex/36.png)
(5)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/9777.png)
![](http://thumb.1010pic.com/pic5/latex/9777.png)
=
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/9777.png)
![](http://thumb.1010pic.com/pic5/latex/9777.png)
![](http://thumb.1010pic.com/pic5/latex/112.png)
=
![](http://thumb.1010pic.com/pic5/latex/9777.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/19137.png)
=
![](http://thumb.1010pic.com/pic5/latex/9777.png)
![](http://thumb.1010pic.com/pic5/latex/13.png)
=
![](http://thumb.1010pic.com/pic5/latex/1154.png)
(6)
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/168.png)
=
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/12579.png)
=
![](http://thumb.1010pic.com/pic5/latex/1261.png)
分析:(1)根据乘法的分配律作答;
(2)根据连续减去两个数,等于减去这两个数的和;
(3)将3.2拆成0.8和4的积,再根据乘法的交换律作答;
(4)、(5)、(6)根据乘法的分配律作答.
点评:解答此题的关键是,运用乘法的分配律及乘法的交换律,使计算简便.
![](http://thumb2018.1010pic.com/images/loading.gif)
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