题目
题型：解答题难度：一般来源：不详
1+（-2）+3+（-4）+…+2009+（-2010）．
答案
=（-1）+（-1）+（-1）+…+
=（-1）×
| 2010 |
| 2 |
=-1005．
核心考点
举一反三
①-
| 1 |
| 2 |
| 1 |
| 3 |
②-
| 1 |
| 2 |
| 1 |
| 3 |
③
| 1 |
| 2 |
| 1 |
| 3 |
④
| 1 |
| 2 |
| 1 |
| 3 |
⑤-
| 1 |
| 3 |
| 1 |
| 4 |
⑥-
| 1 |
| 4 |
| 1 |
| 5 |
-
| 1 |
| 3 |
| 2 |
| 3 |
| 1 |
| 3 |
| 2 |
| 3 |
| 1 |
| 3 |
| 2 |
| 3 |
| A．交换律 |
| B．结合律 |
| C．先用交换律，再用结合律 |
| D．先用结合律，再用交换律 |
| 2010 |
| 2 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 3 |
| 2 |
| 3 |
| 1 |
| 3 |
| 2 |
| 3 |
| 1 |
| 3 |
| 2 |
| 3 |
| A．交换律 |
| B．结合律 |
| C．先用交换律，再用结合律 |
| D．先用结合律，再用交换律 |