第一题:
1:4 - (4 × (4 - 9))
2:4 - 4 ×(4 - 9)
3:4 + (4 × (9 - 4))
4:4 + 4 ×(9 - 4)
5:4 - (4 - 9) × 4
6:4 - ((4 - 9) × 4)
7:4 + (9 - 4) × 4
8:4 + ((9 - 4) × 4)
9:(4 × (9 - 4)) + 4
10:4 × (9 - 4) + 4
11:(9 - 4) × 4 + 4
12:((9 - 4) × 4) + 4
第二题:
14-13+11+12
第三题:
13-(15-14)+12
第四题:
1:(3 + 3 ÷ 7) × 7
2:(3 + (3 ÷ 7)) × 7
3:(3 ÷ 7 + 3) × 7
4:((3 ÷ 7) + 3) × 7
5:7 × (3 + 3 ÷ 7)
6:7 × (3 + (3 ÷ 7))
7:7 × (3 ÷ 7 + 3)
8:7 × ((3 ÷ 7) + 3)
第五题:
1:8 ÷ (3 - 8 ÷ 3)
2:8 ÷ (3 - (8 ÷ 3))