题目内容
7-
-
-
-
-
-
.
| 3 |
| 2 |
| 5 |
| 4 |
| 9 |
| 8 |
| 17 |
| 16 |
| 33 |
| 32 |
| 65 |
| 64 |
分析:先把原式变为7-(
+
+
+
+
+
),括号内的每个分数都可以写成“1+分数单位”的形式,然后再把每个分数单位拆成两个分数相减的形式,通过分数加减相抵消,求出结果.
| 3 |
| 2 |
| 5 |
| 4 |
| 9 |
| 8 |
| 17 |
| 16 |
| 33 |
| 32 |
| 65 |
| 64 |
解答:解:7-
-
-
-
-
-
,
=7-(
+
+
+
+
+
),
=7-(1+
+1+
+1+
+1+
+1+
+1+
),
=7-6-(
+
+
+
+
+
),
=1-(1-
+
-
+
-
+
-
+
-
+
-
),
=1-(1-
),
=
.
| 3 |
| 2 |
| 5 |
| 4 |
| 9 |
| 8 |
| 17 |
| 16 |
| 33 |
| 32 |
| 65 |
| 64 |
=7-(
| 3 |
| 2 |
| 5 |
| 4 |
| 9 |
| 8 |
| 17 |
| 16 |
| 33 |
| 32 |
| 65 |
| 64 |
=7-(1+
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 64 |
=7-6-(
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 64 |
=1-(1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 32 |
| 1 |
| 64 |
=1-(1-
| 1 |
| 64 |
=
| 1 |
| 64 |
点评:解答这类问题,应仔细审题,通过分数的拆分,达到简算的目的.
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