2,2,6,9怎样做24点

1: 2 × (2 × 9 - 6)
2: 2 × ((2 × 9) - 6)
3: 2 × (6 ÷ 2 + 9)
4: 2 × ((6 ÷ 2) + 9)
5: 2 × (9 × 2 - 6)
6: 2 × ((9 × 2) - 6)
7: 2 × (9 + 6 ÷ 2)
8: 2 × (9 + (6 ÷ 2))
9: (2 × 9 - 6) × 2
10: ((2 × 9) - 6) × 2
11: (6 ÷ 2 + 9) × 2
12: ((6 ÷ 2) + 9) × 2
13: (9 × 2 - 6) × 2
14: ((9 × 2) - 6) × 2
15: (9 + 6 ÷ 2) × 2
16: (9 + (6 ÷ 2)) × 2

这四个数怎么算也不会算到24点的。

佩服