题目内容
(9+
)+(9+
×2)+(9+
×3)+…+(9+
×20)=______.
| 17 |
| 99 |
| 17 |
| 99 |
| 17 |
| 99 |
| 17 |
| 99 |
原式=20×9+(
×1+
×2+… +
×20),
=180+(1+2+…+20)×
,
=180+210×
,
=180+36
,
=216
;
故答案为:216
.
| 17 |
| 99 |
| 17 |
| 99 |
| 17 |
| 99 |
=180+(1+2+…+20)×
| 17 |
| 99 |
=180+210×
| 17 |
| 99 |
=180+36
| 2 |
| 33 |
=216
| 2 |
| 33 |
故答案为:216
| 2 |
| 33 |
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