7.8.9.10算24点的答案：
1:8 × (9 ÷ (10 - 7))
2:8 × 9 ÷(10 - 7)
3:(8 × 9) ÷ (10 - 7)
4:(8 ÷ (10 - 7)) × 9
5:8 ÷ (10 - 7) × 9
6:8 ÷ ((10 - 7) ÷ 9)
7:9 × (8 ÷ (10 - 7))
8:9 × 8 ÷(10 - 7)
9:(9 × 8) ÷ (10 - 7)
10:(9 ÷ (10 - 7)) × 8
11:9 ÷ (10 - 7) × 8
12:9 ÷ ((10 - 7) ÷ 8)
7.8.8.10算24点的答案：
1:8 × 10 - 7 × 8
2:(8 × 10) - 7 × 8
3:8 × 10 -(7 × 8)
4:(8 × 10) - (7 × 8)
5:8 × 10 - 8 × 7
6:(8 × 10) - 8 × 7
7:8 × 10 -(8 × 7)
8:(8 × 10) - (8 × 7)
9:10 × 8 - 7 × 8
10:(10 × 8) - 7 × 8
11:10 × 8 -(7 × 8)
12:(10 × 8) - (7 × 8)
13:10 × 8 - 8 × 7
14:(10 × 8) - 8 × 7
15:10 × 8 -(8 × 7)
16:(10 × 8) - (8 × 7)