题目内容
9×
+12×
+15×
+18×
+21×
+24×
+27×
+30×
．
| 1 |
| 36 |
| 1 |
| 48 |
| 1 |
| 75 |
| 1 |
| 90 |
| 1 |
| 126 |
| 1 |
| 144 |
| 1 |
| 216 |
| 1 |
| 240 |
分析：通过观察，此题应先约分，然后通分计算即可．
解答：解：9×
+12×
+15×
+18×
+21×
+24×
+27×
+30×
，
=
+
+
+
+
+
+
+
，
=
+
+
+
，
=
+
+
+
，
=
．
| 1 |
| 36 |
| 1 |
| 48 |
| 1 |
| 75 |
| 1 |
| 90 |
| 1 |
| 126 |
| 1 |
| 144 |
| 1 |
| 216 |
| 1 |
| 240 |
=
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 5 |
| 1 |
| 6 |
| 1 |
| 6 |
| 1 |
| 8 |
| 1 |
| 8 |
=
| 1 |
| 2 |
| 2 |
| 5 |
| 1 |
| 3 |
| 1 |
| 4 |
=
| 30 |
| 60 |
| 24 |
| 60 |
| 20 |
| 60 |
| 15 |
| 60 |
=
| 89 |
| 60 |
点评：完成此题，主要运用了约分和通分计算．
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