Evaluate $9+\left(-7\right)-4$9+(−7)−4

Evaluate $-9+6-\left(-17\right)$−9+6−(−17)

Evaluate $20+\left(-14\right)-\left(-2\right)-18$20+(−14)−(−2)−18

Evaluate $6-\left(13-3\right)$6−(13−3)