用5 7 8 9 四个数凑成24 有几种方法?

1:(5 + 7 - 9) × 8
2:((5 + 7) - 9) × 8
3:(5 + (7 - 9)) × 8
4:5 × 8 -(7 + 9)
5:(5 × 8) - (7 + 9)
6:5 × 8 - 7 - 9
7:(5 × 8) - 7 - 9
8:(5 × 8 - 7) - 9
9:((5 × 8) - 7) - 9
10:5 × 8 -(9 + 7)
11:(5 × 8) - (9 + 7)
12:5 × 8 - 9 - 7
13:(5 × 8) - 9 - 7
14:(5 × 8 - 9) - 7
15:((5 × 8) - 9) - 7
16:(5 - 9 + 7) × 8
17:((5 - 9) + 7) × 8
18:(5 - (9 - 7)) × 8
19:(7 + 5 - 9) × 8
20:((7 + 5) - 9) × 8
21:(7 + (5 - 9)) × 8
22:(7 - 9 + 5) × 8
23:((7 - 9) + 5) × 8
24:(7 - (9 - 5)) × 8
25:8 × (5 + 7 - 9)
26:8 × ((5 + 7) - 9)
27:8 × (5 + (7 - 9))
28:8 × 5 -(7 + 9)
29:(8 × 5) - (7 + 9)
30:8 × 5 - 7 - 9
31:(8 × 5) - 7 - 9
32:(8 × 5 - 7) - 9
33:((8 × 5) - 7) - 9
34:8 × (5 - 9 + 7)
35:8 × ((5 - 9) + 7)
36:8 × 5 -(9 + 7)
37:(8 × 5) - (9 + 7)
38:8 × 5 - 9 - 7
39:(8 × 5) - 9 - 7
40:(8 × 5 - 9) - 7
41:((8 × 5) - 9) - 7
42:8 × (5 - (9 - 7))
43:8 × (7 + 5 - 9)
44:8 × ((7 + 5) - 9)
45:8 × (7 + (5 - 9))
46:8 × (7 - 9 + 5)
47:8 × ((7 - 9) + 5)
48:8 × (7 - (9 - 5))