题目内容
| 1 |
| 2 |
| 5 |
| 4 |
| 9 |
| 8 |
| 17 |
| 16 |
| 33 |
| 32 |
| 65 |
| 64 |
| 129 |
| 128 |
分析:通过观察,从第二个分数开始,每个分数都比1大一个分数单位,因此把每个分数拆分成1+分数单位的形式,然后把整数与分数分别相加,在把每个分数拆分成两个分数相减的形式,通过加减数相抵消的方法,求出结果.
解答:解:
+
+
+
+
+
+
,
=
+(1+
)+(1+
)+(1+
)+(1+
)+(1+
)+(1+
),
=6+(
+
+
+
+
+
+
),
=6+(1-
)+(
-
)+(
-
)+(
-
)+(
-
)+(
-
)+(
-
),
=6+1-
,
=6
.
| 1 |
| 2 |
| 5 |
| 4 |
| 9 |
| 8 |
| 17 |
| 16 |
| 33 |
| 32 |
| 65 |
| 64 |
| 129 |
| 128 |
=
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 64 |
| 1 |
| 128 |
=6+(
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 64 |
| 1 |
| 128 |
=6+(1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 32 |
| 1 |
| 64 |
| 1 |
| 64 |
| 1 |
| 128 |
=6+1-
| 1 |
| 128 |
=6
| 127 |
| 128 |
点评:通过拆分法解题,拆开后的分数可以相互抵消.
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笔算.
|
(1)9 +69= |
(2)80 -12= |
(3)98 -58= |
(4)46 +54= |