3,6,7,9四个数,算24

1: 3 × (6 - 7 + 9)
2: 3 × ((6 - 7) + 9)
3: 3 × (6 - (7 - 9))
4: 3 - (6 - 9) × 7
5: 3 - ((6 - 9) × 7)
6: 3 × (6 + 9 - 7)
7: 3 × ((6 + 9) - 7)
8: 3 × (6 + (9 - 7))
9: 3 - (7 × (6 - 9))
10: 3 - 7 ×(6 - 9)
11: 3 × 7 - 6 + 9
12: (3 × 7) - 6 + 9
13: (3 × 7 - 6) + 9
14: ((3 × 7) - 6) + 9
15: 3 × 7 -(6 - 9)
16: (3 × 7) - (6 - 9)
17: 3 + (7 × (9 - 6))
18: 3 + 7 ×(9 - 6)
19: 3 × 7 + 9 - 6
20: (3 × 7) + 9 - 6
21: (3 × 7 + 9) - 6
22: ((3 × 7) + 9) - 6
23: 3 × 7 +(9 - 6)
24: (3 × 7) + (9 - 6)
25: 3 + (9 - 6) × 7
26: 3 + ((9 - 6) × 7)
27: 3 × (9 + 6 - 7)
28: 3 × ((9 + 6) - 7)
29: 3 × (9 + (6 - 7))
30: 3 × (9 - 7 + 6)
31: 3 × ((9 - 7) + 6)
32: 3 × (9 - (7 - 6))
33: (6 - 7 + 9) × 3
34: ((6 - 7) + 9) × 3
35: (6 - (7 - 9)) × 3
36: 6 × (7 - 9 ÷ 3)
37: 6 × (7 - (9 ÷ 3))
38: (6 + 9 -