用2277算24点

2 × (7 - 2 + 7)

我就不登陆了，当做好事吧。

2 × (7 - 2 + 7)

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

:(7-(2-7))*2=24

7-(2-7)*2=24