题目内容
| 1 |
| 3 |
| 3 |
| 4 |
| 2 |
| 5 |
| 5 |
| 7 |
| 7 |
| 8 |
| 9 |
| 20 |
| 10 |
| 21 |
| 11 |
| 24 |
| 19 |
| 35 |
分析：通过分析式中数据发现：
=
+
，
=
+
，
=
+
，
=
+
=
+
，所以可将式中的后四个分数拆分后根据加法结合律进行巧算．
| 9 |
| 20 |
| 1 |
| 4 |
| 1 |
| 5 |
| 10 |
| 21 |
| 1 |
| 7 |
| 1 |
| 3 |
| 11 |
| 24 |
| 1 |
| 3 |
| 1 |
| 8 |
| 19 |
| 35 |
| 14 |
| 35 |
| 5 |
| 35 |
| 2 |
| 5 |
| 1 |
| 7 |
解答：解：
+
+
+
+
+
+
+
+
=
+
+
+
+
+
+
+
+
+
+
+
+
，
=
+
+
+
+
+
+
+
+
+
+
+
+
，
=（
+
+
）+（
+
）+（
+
+
）+（
+
+
）+（
+
），
=1+1+1+1+1，
=5．
| 1 |
| 3 |
| 3 |
| 4 |
| 2 |
| 5 |
| 5 |
| 7 |
| 7 |
| 8 |
| 9 |
| 20 |
| 10 |
| 21 |
| 11 |
| 24 |
| 19 |
| 35 |
=
| 1 |
| 3 |
| 3 |
| 4 |
| 2 |
| 5 |
| 5 |
| 7 |
| 7 |
| 8 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 3 |
| 1 |
| 7 |
| 1 |
| 3 |
| 1 |
| 8 |
| 14 |
| 35 |
| 5 |
| 35 |
=
| 1 |
| 3 |
| 3 |
| 4 |
| 2 |
| 5 |
| 5 |
| 7 |
| 7 |
| 8 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 3 |
| 1 |
| 7 |
| 1 |
| 3 |
| 1 |
| 8 |
| 2 |
| 5 |
| 1 |
| 7 |
=（
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |
| 3 |
| 4 |
| 1 |
| 4 |
| 2 |
| 5 |
| 1 |
| 5 |
| 2 |
| 5 |
| 5 |
| 7 |
| 1 |
| 7 |
| 1 |
| 7 |
| 7 |
| 8 |
| 1 |
| 8 |
=1+1+1+1+1，
=5．
点评：在分数的运算中，
+
=
．
| 1 |
| n |
| 1 |
| m |
| n+m |
| nm |
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