Here is some important terminology, change. In science and math change is symbolized with the Greek letter capital delta, Δ. It looks like a triangle. When every you see this symbol it means the the change in the concept that follows. For example "v" stands for velocity and therefore "Δv" means the final velocity in time minus the initial velocity in time. (Whenever a "change" is calculated the "final" value is typically the one that occurs later in time.) A car is traveling along the road at 40 mph. After traveling for 150 meters it is now traveling at 60 mph. The Δv (pronounced "change in velocity") is 20 mph. That's 60 mph – 40 mph = 20 mph. The 60 mph comes first in this expression because 60 mph came later in time. Traveling at 40 mph happened earlier in time in the description of the motion.

The change in position has is own unique word. It is called displacement. Displacement is the final position minus the initial position. x_final- x_initial = displacement. The path an object took between these two locations is ignored. Unlike the word "distance," displacement has a direction. The direction is indicated as either the positive or negative direction.