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