What is the net force if you push a cart to the right with N of force and a friend pushes the cart to the left with N of force?

The net force on the crate is 70 N to the left while it's moving to the left,

and 20 N to the right while it's moving to the right.

If the 100N force and the 50N force are acting on it at the same time,

then the net force on the crate is 20 N towards the left.