| 序号 | 题目:9,10,12,13 | |
|---|---|---|
| 1 | ((12 + 9) + 13) − 10 | |
| 2 | ((13 + 12) − 10) + 9 | |
| 3 | ((13 + 12) + 9) − 10 | |
| 4 | ((13 + 9) + 12) − 10 | |
| 5 | (13 + 9) + (12 − 10) | |
| 6 | (12 + (13 − 10)) + 9 | |
| 7 | (13 + 12) − (10 − 9) | |
| 8 | (13 + (12 − 10)) + 9 | |
| 9 | (12 + 9) + (13 − 10) | |
| 10 | 12 + ((13 + 9) − 10) | |
| 11 | 13 + (12 − (10 − 9)) | |
| 12 | 13 + (9 + (12 − 10)) | |
| 13 | 13 + ((12 + 9) − 10) | |
| 14 | 12 + (9 + (13 − 10)) | |
| 15 | 12 + (13 − (10 − 9)) | |