题目内容
| 17 |
| 77 |
| 17 |
| 77 |
| 17 |
| 77 |
| 17 |
| 77 |
| 17 |
| 77 |
分析:利用乘法结合律,提取
,括号内是10+9+8+7+…+1,根据高斯求和求出括号内是55,进而即可得解.
| 17 |
| 77 |
解答:解:
×10+
×9+
×8+…+
×2+
=
×(10+9+8+…+1)
=
×55
=
=
.
故答案为:
.
| 17 |
| 77 |
| 17 |
| 77 |
| 17 |
| 77 |
| 17 |
| 77 |
| 17 |
| 77 |
=
| 17 |
| 77 |
=
| 17 |
| 77 |
=
| 935 |
| 77 |
=
| 85 |
| 7 |
故答案为:
| 85 |
| 7 |
点评:灵活应用利用乘法分配律和高斯求和是解决此题的关键.
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