题目内容
简算：
①
| ②1
| ③1
| ||||||||||||||||||||||
④
| ⑤1
| ⑥
|
考点：分数的简便计算
专题：运算定律及简算
分析：①利用减法的性质可得原式=
-
+
，再利用加法交换与结合律简算；
②④⑤⑥利用加法交换与结合律简算；
③利用减法的性质可得原式=1
-
-
，再利用加法交换与结合律简算．
| 5 |
| 7 |
| 8 |
| 15 |
| 2 |
| 7 |
②④⑤⑥利用加法交换与结合律简算；
③利用减法的性质可得原式=1
| 8 |
| 9 |
| 7 |
| 8 |
| 8 |
| 9 |
解答：
解：①
-（
-
）
=
-
+
=
+
-
=1-
=
；
②1
+
+
=1
+
+
=2+
=2
；
③1
-（
+
）
=1
-
-
=1
-
-
=1-
=
；
④
-
-
+
=
+
-
-
=1-
=
；
⑤1
-
-
=1
-
-
=1-
=
；
⑥
-
+
+
=
+
+
-
=
．
| 5 |
| 7 |
| 8 |
| 15 |
| 2 |
| 7 |
=
| 5 |
| 7 |
| 8 |
| 15 |
| 2 |
| 7 |
=
| 5 |
| 7 |
| 2 |
| 7 |
| 8 |
| 15 |
=1-
| 8 |
| 15 |
=
| 7 |
| 15 |
②1
| 5 |
| 12 |
| 5 |
| 15 |
| 7 |
| 12 |
=1
| 5 |
| 12 |
| 7 |
| 12 |
| 5 |
| 15 |
=2+
| 5 |
| 15 |
=2
| 1 |
| 3 |
③1
| 8 |
| 9 |
| 7 |
| 8 |
| 8 |
| 9 |
=1
| 8 |
| 9 |
| 7 |
| 8 |
| 8 |
| 9 |
=1
| 8 |
| 9 |
| 8 |
| 9 |
| 7 |
| 8 |
=1-
| 7 |
| 8 |
=
| 1 |
| 8 |
④
| 3 |
| 8 |
| 2 |
| 5 |
| 1 |
| 5 |
| 5 |
| 8 |
=
| 3 |
| 8 |
| 5 |
| 8 |
| 2 |
| 5 |
| 1 |
| 5 |
=1-
| 3 |
| 5 |
=
| 2 |
| 5 |
⑤1
| 3 |
| 4 |
| 13 |
| 20 |
| 3 |
| 4 |
=1
| 3 |
| 4 |
| 3 |
| 4 |
| 13 |
| 20 |
=1-
| 13 |
| 20 |
=
| 7 |
| 20 |
⑥
| 7 |
| 9 |
| 1 |
| 3 |
| 3 |
| 9 |
| 1 |
| 3 |
=
| 7 |
| 9 |
| 3 |
| 9 |
| 1 |
| 3 |
| 1 |
| 3 |
=
| 10 |
| 9 |
点评：完成本题要注意分析式中数据的特点，利用加法交换与结合律简算．
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