9 ,9 ,3 ,7只能用一次怎么算等于24
问题描述：
9 ,9 ,3 ,7只能用一次怎么算等于24
答
1: (9 + 9 × 7) ÷ 3
2: (9 + (9 × 7)) ÷ 3
3: (9 ÷ 9 + 7) × 3
4: ((9 ÷ 9) + 7) × 3
5: (9 + 7 × 9) ÷ 3
6: (9 + (7 × 9)) ÷ 3
7: (9 - 7) × (9 + 3)
8: (9 × 7 + 9) ÷ 3
9: ((9 × 7) + 9) ÷ 3
10: (9 - 7) × (3 + 9)
11: (9 + 3) × (9 - 7)
12: (7 + 9 ÷ 9) × 3
13: (7 + (9 ÷ 9)) × 3
14: (7 × 9 + 9) ÷ 3
15: ((7 × 9) + 9) ÷ 3
16: (3 + 9) × (9 - 7)
17: 3 × (9 ÷ 9 + 7)
18: 3 × ((9 ÷ 9) + 7)
19: 3 × (7 + 9 ÷ 9)
20: 3 × (7 + (9 ÷ 9))
答
3*(7+9/9)=24
答
(9-7)×（9+3）=24