| 序号 | 题目：1,3,4,9 | |
|---|---|---|
| 1 | ((9 − 3) × 1) × 4 | |
| 2 | ((4 + 1) × 3) + 9 | |
| 3 | ((9 × 3) − 4) + 1 | |
| 4 | ((9 × 1) − 3) × 4 | |
| 5 | ((9 − 3) × 4) × 1 | |
| 6 | ((9 × 3) + 1) − 4 | |
| 7 | (9 − 3) × (4 × 1) | |
| 8 | (9 × 3) − (4 − 1) | |
| 9 | (9 × (4 − 1)) − 3 | |
| 10 | (9 − (3 × 1)) × 4 | |
| 11 | ((9 − 3) × 4) ÷ 1 | |
| 12 | ((9 ÷ 1) − 3) × 4 | |
| 13 | ((9 − 3) ÷ 1) × 4 | |
| 14 | (9 − 3) × (4 ÷ 1) | |
| 15 | (9 − (3 ÷ 1)) × 4 | |
| 16 | (9 − 3) ÷ (1 ÷ 4) | |
| 17 | 4 ÷ (1 ÷ (9 − 3)) | |