题目内容
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考点:分数的巧算
专题:计算问题(巧算速算)
分析:通过观察,此题可分为两部分,即(
+
+
)+(
+
+
+
+
),每一部分中的后一个分数都是前一个分数的
,因此可通过拆分,通过加减相互抵消,解决问题.
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| 496 |
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| 2 |
解答:
解:
+
+
+
+
+
+
+
=(
+
+
)+(
+
+
+
+
)
=(1-
+
-
+
-
)+(
+
-
+
-
+
-
+
-
)
=(1-
)+(
-
)
=
+(
-
)
=
+
=
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| 1 |
| 4 |
| 1 |
| 8 |
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| 31 |
| 1 |
| 62 |
| 1 |
| 124 |
| 1 |
| 248 |
| 1 |
| 496 |
=(
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 31 |
| 1 |
| 62 |
| 1 |
| 124 |
| 1 |
| 248 |
| 1 |
| 496 |
=(1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 31 |
| 1 |
| 31 |
| 1 |
| 62 |
| 1 |
| 62 |
| 1 |
| 124 |
| 1 |
| 124 |
| 1 |
| 248 |
| 1 |
| 248 |
| 1 |
| 496 |
=(1-
| 1 |
| 8 |
| 2 |
| 31 |
| 1 |
| 496 |
=
| 7 |
| 8 |
| 32 |
| 496 |
| 1 |
| 496 |
=
| 7 |
| 8 |
| 1 |
| 16 |
=
| 15 |
| 16 |
点评:仔细观察题目中数字构成的特点和规律,运用拆分的方法,解决问题.
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