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