题目内容
(2012?长春)计算下面各题能简便的尽量简便
(1)24×(
+
-
)
(2)[
×(
-0.25)+
]÷0.5
(3)0.374×48+0.62×37.4-3.74
(4)0.125×
+
×8.25+12.5%
(5)2012÷2012
+
.
(1)24×(
| 3 |
| 4 |
| 5 |
| 6 |
| 2 |
| 3 |
(2)[
| 4 |
| 7 |
| 3 |
| 5 |
| 3 |
| 10 |
(3)0.374×48+0.62×37.4-3.74
(4)0.125×
| 3 |
| 4 |
| 1 |
| 8 |
(5)2012÷2012
| 2012 |
| 2013 |
| 1 |
| 2014 |
分析:(1)直接运用乘法的分配律 计算会更加简便.
(2)按照先计算小括号内部的在计算中括号内的顺序进行计算.
(3)把0.62×37.4改写成62×0.374,把3.74改成0.374×10后再运用乘法的分配律进行计算.
(4)把
转化成0.125把12.5%转化成0.125后再运用乘法的分配律进行计算会更加简便.
(5)先把2012
化成假分数分子用式子来表示,然后再进行计算.
(2)按照先计算小括号内部的在计算中括号内的顺序进行计算.
(3)把0.62×37.4改写成62×0.374,把3.74改成0.374×10后再运用乘法的分配律进行计算.
(4)把
| 1 |
| 8 |
(5)先把2012
| 2012 |
| 2013 |
解答:解:(1)24×(
+
-
),
=24×
+24×
-24×
,
=18+20-16,
=22;
(2)[
×(
-0.25)+
]÷0.5,
=[
×(
-
)+
],
=
×(
-
)+
,
=
×
+
,
=
+
,
=
;
(3)0.374×48+0.62×37.4-3.74,
=0.374×48+62×0.374-0.374×10,
=0.374×(48+62-10),
=0.374×100,
=37.4;
(4)0.125×
+
×8.25+12.5%
=0.125×0.75+0.125×8.25+0.125,
=0.125×(0.75+8.25+1),
=0.125×10,
=1.25;
(5)2012÷2012
+
,
=2012÷
+
,
=2012÷
+
,
=2012×
+
,
=
+
,
=1.
| 3 |
| 4 |
| 5 |
| 6 |
| 2 |
| 3 |
=24×
| 3 |
| 4 |
| 5 |
| 6 |
| 2 |
| 3 |
=18+20-16,
=22;
(2)[
| 4 |
| 7 |
| 3 |
| 5 |
| 3 |
| 10 |
=[
| 4 |
| 7 |
| 3 |
| 5 |
| 1 |
| 4 |
| 3 |
| 10 |
=
| 4 |
| 7 |
| 12 |
| 20 |
| 5 |
| 20 |
| 3 |
| 10 |
=
| 4 |
| 7 |
| 7 |
| 20 |
| 3 |
| 10 |
=
| 2 |
| 10 |
| 3 |
| 10 |
=
| 1 |
| 2 |
(3)0.374×48+0.62×37.4-3.74,
=0.374×48+62×0.374-0.374×10,
=0.374×(48+62-10),
=0.374×100,
=37.4;
(4)0.125×
| 3 |
| 4 |
| 1 |
| 8 |
=0.125×0.75+0.125×8.25+0.125,
=0.125×(0.75+8.25+1),
=0.125×10,
=1.25;
(5)2012÷2012
| 2012 |
| 2013 |
| 1 |
| 2014 |
=2012÷
| 2012×2013+2012 |
| 2013 |
| 1 |
| 2014 |
=2012÷
| 2012×(2013+1) |
| 2013 |
| 1 |
| 2014 |
=2012×
| 2013 |
| 2012×2014 |
| 1 |
| 2014 |
=
| 2013 |
| 2014 |
| 1 |
| 2014 |
=1.
点评:本题主要考查了乘法分配律在计算中的灵活运用,同时考查了学生的计算技巧和 运算能力.
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