求助啊！各位数学高手帮帮忙

3*7+4-1

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