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