都用正数计算即可,因为5=-(-5)!
1:(3 - 7) × (5 - 11)
2:(5 - 11) × (3 - 7)
3:(7 - 3) × (11 - 5)
4:(7 × 11 - 5) ÷ 3
5:((7 × 11) - 5) ÷ 3
6:(11 - 5) × (7 - 3)