1: 6 - (5 - 7) × 9
2: 6 - ((5 - 7) × 9)
3: 6 + (7 - 5) × 9
4: 6 + ((7 - 5) × 9)
5: 6 - (9 × (5 - 7))
6: 6 - 9 ×(5 - 7)
7: 6 + (9 × (7 - 5))
8: 6 + 9 ×(7 - 5)
9: (7 - 5) × 9 + 6
10: ((7 - 5) × 9) + 6
11: (9 × (7 - 5)) + 6
12: 9 × (7 - 5) + 6