题目内容
(2011?历城区模拟)用简便方法计算.
25×(100+4)
×20-
×3-
2008×
.
25×(100+4)
| 3 |
| 8 |
| 3 |
| 8 |
| 3 |
| 8 |
2008×
| 2006 |
| 2007 |
分析:(1)运用乘法分配律简算;
(2)运用乘法分配律的逆运算简算;
(3)把2008看作2007+1,运用乘法分配律简算.
(2)运用乘法分配律的逆运算简算;
(3)把2008看作2007+1,运用乘法分配律简算.
解答:解:(1)25×(100+4),
=25×100+25×4,
=2500+100,
=2600;
(2)
×20-
×3-
,
=
×(20-3-1),
=
×16,
=6;
(3)2008×
,
=(2007+1)×
,
=2007×
+
,
=2006+
,
=2006
.
=25×100+25×4,
=2500+100,
=2600;
(2)
| 3 |
| 8 |
| 3 |
| 8 |
| 3 |
| 8 |
=
| 3 |
| 8 |
=
| 3 |
| 8 |
=6;
(3)2008×
| 2006 |
| 2007 |
=(2007+1)×
| 2006 |
| 2007 |
=2007×
| 2006 |
| 2007 |
| 2006 |
| 2007 |
=2006+
| 2006 |
| 2007 |
=2006
| 2006 |
| 2007 |
点评:此题重点考查了乘法分配律的掌握与运用情况,注意运用的灵活性.
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