题目内容
| 1 |
| 1+1 |
| 2 |
| 1+2 |
| 3 |
| 1+3 |
| 2010 |
| 1+2010 |
| ||
1+
|
| ||||
1
|
| ||
1+
|
分析:通过试探,此题运用加法交换律与结合律简算,因为
+
=1,
+
=1,…,共有2009个1,然后加上第一项
即可.
| 2 |
| 1+2 |
| ||
1+
|
| 3 |
| 1+3 |
| ||
1+
|
| 1 |
| 2 |
解答:解:
+
+
+…+
+
+
+…+
,
=
+(
+
)+(
+
)+…+(
+
),
=
+(
+
)+(
+
)+…+(
+
),
=
+1+1+…+1,
=
+2009,
=2009
.
| 1 |
| 1+1 |
| 2 |
| 1+2 |
| 3 |
| 1+3 |
| 2010 |
| 1+2010 |
| ||
1+
|
| ||
1+
|
| ||
1+
|
=
| 1 |
| 1+1 |
| 2 |
| 1+2 |
| ||
1+
|
| 3 |
| 1+3 |
| ||
1+
|
| 2010 |
| 1+2010 |
| ||
1+
|
=
| 1 |
| 2 |
| 2 |
| 3 |
| 1 |
| 3 |
| 3 |
| 4 |
| 1 |
| 4 |
| 2010 |
| 2011 |
| 1 |
| 2011 |
=
| 1 |
| 2 |
=
| 1 |
| 2 |
=2009
| 1 |
| 2 |
点评:仔细观察,通过试探,找出规律,运用运算定律,进行计算.
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