题目内容
计算:
+
+
+
+…+
.
| 1 |
| 6 |
| 1 |
| 12 |
| 1 |
| 20 |
| 1 |
| 30 |
| 1 |
| 2005×2006 |
考点:分数的巧算
专题:计算问题(巧算速算)
分析:把每个分数拆成两个分数相减的形式,然后通过加减相互抵消,求得结果.
解答:
解:
+
+
+
+…+
=
-
+
-
+
-
+…+
-
=
-
=
| 1 |
| 6 |
| 1 |
| 12 |
| 1 |
| 20 |
| 1 |
| 30 |
| 1 |
| 2005×2006 |
=
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 2005 |
| 1 |
| 2006 |
=
| 1 |
| 2 |
| 1 |
| 2006 |
=
| 501 |
| 1003 |
点评:此题解答的关键在于把每个分数进行拆分,达到简算的目的.
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