题目内容
1
+2
+3
+4
+5
+6
+7
.
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 6 |
| 1 |
| 7 |
| 1 |
| 8 |
分析:此题中的数字均为带分数,可把每个分数拆成整数与分数的和,然后把整数与分数分别相加,分数部分再运用加法交换律与结合律简算.
解答:解:1
+2
+3
+4
+5
+6
+7
,
=(1+2+3+4+5+6+7)+(
+
+
+
+
+
+
),
=28+(
+
+
)+(
+
+
+
),
=28+(
+
+
-
)+
,
=29+
,
=29
.
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 6 |
| 1 |
| 7 |
| 1 |
| 8 |
=(1+2+3+4+5+6+7)+(
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 6 |
| 1 |
| 7 |
| 1 |
| 8 |
=28+(
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 6 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 7 |
| 1 |
| 8 |
=28+(
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 201 |
| 280 |
=29+
| 201 |
| 280 |
=29
| 201 |
| 280 |
点评:注意观察题目中数字构成的特点和规律,善于灵活运用运算定律或运算技巧,巧妙解答.
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