2 4 7 12 如何算24点
问题描述：
2 4 7 12 如何算24点
答
1:(2 + 7) × 4 - 12
2:((2 + 7) × 4) - 12
3:(4 × (2 + 7)) - 12
4:4 × (2 + 7) - 12
5:(4 × (7 + 2)) - 12
6:4 × (7 + 2) - 12
7:(7 + 2) × 4 - 12
8:((7 + 2) × 4) - 12
9:12 ÷ (4 - 7 ÷ 2)
10:12 ÷ (4 - (7 ÷ 2))