题目内容
2009×
+
.
| 2007 |
| 2008 |
| 1 |
| 2008 |
分析:首先把2009拆成2008+1,利用乘法分配律展开,再进一步计算即可.
解答:解:2009×
+
,
=(2008+1)×
+
,
=2008×
+
+
,
=2007+1,
=2008.
| 2007 |
| 2008 |
| 1 |
| 2008 |
=(2008+1)×
| 2007 |
| 2008 |
| 1 |
| 2008 |
=2008×
| 2007 |
| 2008 |
| 2007 |
| 2008 |
| 1 |
| 2008 |
=2007+1,
=2008.
点评:解答此题的关键是抓住数的特点,灵活选用运算定律进行简算.
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