Knowing what they are and what they stand for are two completely different things
Knowing it's a greek letter let's us know they used it to write letters and the like, it gives us no clue at all as to what it pertains to in physics or other maths.
Obtaining a firmer grasp of the English...
I learn the reasoning behind the equations, this let's you forget the equations formal setup while still being able to work it out
initial speed/gravity = time it takes to reach the top
so in this particular one it would be
20 divided by 9.8 (constant acceleration caused by gravity)...