| 序号 | 题目:4,7,8,13 | |
|---|---|---|
| 1 | ((8 + 7) + 13) − 4 | |
| 2 | ((13 + 7) − 4) + 8 | |
| 3 | ((13 + 8) + 7) − 4 | |
| 4 | ((13 + 8) − 4) + 7 | |
| 5 | ((13 − 4) + 7) + 8 | |
| 6 | ((13 − 4) + 8) + 7 | |
| 7 | ((13 + 7) + 8) − 4 | |
| 8 | (13 + 8) + (7 − 4) | |
| 9 | (8 + 7) + (13 − 4) | |
| 10 | (13 + 7) + (8 − 4) | |
| 11 | (13 + (7 − 4)) + 8 | |
| 12 | (13 − 7) × (8 − 4) | |
| 13 | (13 + (8 − 4)) + 7 | |
| 14 | 13 + ((8 + 7) − 4) | |
| 15 | 13 + (8 + (7 − 4)) | |
| 16 | 13 + (7 + (8 − 4)) | |