题目内容
12×[(
|
81÷14+17×
| ||||||||||
|
|
分析:①先算小括号,再算中括号,再算乘法;
②将除法转化为乘法,再根据乘法分配律简便计算;
③先算小括号内的乘法,再算加法,最后计算括号外的乘法;
④将2008写成(2007+1)的形式,再根据乘法分配律简便计算.
②将除法转化为乘法,再根据乘法分配律简便计算;
③先算小括号内的乘法,再算加法,最后计算括号外的乘法;
④将2008写成(2007+1)的形式,再根据乘法分配律简便计算.
解答:解:12×[(
-
)×3]
=12×[
×3]
=12×
=42;
81÷14+17×
=81×
+17×
=(81+17)×
=98×
=7;
×(
+
÷
)
=
×(
+
)
=
×
=
;
×2008
=
×(2007+1)
=
×2007+
×1
=2006+
=2006
.
| 11 |
| 6 |
| 2 |
| 3 |
=12×[
| 7 |
| 6 |
=12×
| 7 |
| 2 |
=42;
81÷14+17×
| 1 |
| 14 |
=81×
| 1 |
| 14 |
| 1 |
| 14 |
=(81+17)×
| 1 |
| 14 |
=98×
| 1 |
| 14 |
=7;
| 3 |
| 5 |
| 1 |
| 7 |
| 8 |
| 21 |
| 2 |
| 3 |
=
| 3 |
| 5 |
| 1 |
| 7 |
| 4 |
| 7 |
=
| 3 |
| 5 |
| 5 |
| 7 |
=
| 3 |
| 7 |
| 2006 |
| 2007 |
=
| 2006 |
| 2007 |
=
| 2006 |
| 2007 |
| 2006 |
| 2007 |
=2006+
| 2006 |
| 2007 |
=2006
| 2006 |
| 2007 |
点评:考查了分数的简便计算,注意灵活运用公式可以使计算简便.
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