题目内容
2+3+5+13+
+
+
+
=
| 2 |
| 99 |
| 11 |
| 63 |
| 25 |
| 35 |
| 5 |
| 15 |
24
| 8 |
| 33 |
24
.| 8 |
| 33 |
分析:先把
拆成
+
,把分数能够约分的先约分,并把有些分数拆成两个分数相减的形式,原式变为23+
-
+
-
+
+
+
,运用加法交换律和结合律计算,得出结果.
| 11 |
| 63 |
| 2 |
| 63 |
| 9 |
| 63 |
| 1 |
| 9 |
| 1 |
| 11 |
| 1 |
| 7 |
| 1 |
| 9 |
| 1 |
| 7 |
| 5 |
| 7 |
| 1 |
| 3 |
解答:解:2+3+5+13+
+
+
+
,
=2+3+5+13+
+
+
+
+
,
=23+
-
+
-
+
+
+
,
=23-
+1+
,
=24-
+
,
=24+
,
=24
.
| 2 |
| 99 |
| 11 |
| 63 |
| 25 |
| 35 |
| 5 |
| 15 |
=2+3+5+13+
| 2 |
| 99 |
| 2 |
| 63 |
| 9 |
| 63 |
| 5 |
| 7 |
| 1 |
| 3 |
=23+
| 1 |
| 9 |
| 1 |
| 11 |
| 1 |
| 7 |
| 1 |
| 9 |
| 1 |
| 7 |
| 5 |
| 7 |
| 1 |
| 3 |
=23-
| 1 |
| 11 |
| 1 |
| 3 |
=24-
| 3 |
| 33 |
| 11 |
| 33 |
=24+
| 8 |
| 33 |
=24
| 8 |
| 33 |
点评:考查了学生的审题以及对分数拆项的能力,此题主要是运用所学性质与定律以及数与数之间的特殊关系灵活进行.
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