Percent proportion is just any positive fraction, which, as it was mentioned, can exceed whether the percentage has a fixed denominator, equal to 100. So, although there's no intuitive difference, there is a slight distinction in the mathematical sense. It is also the amount of items in a mixture. Example: two eggs for every two cups of flour.
percent equation is a part of something equals to percent times the whole
part = percent x whole
Example: what is 80% of 20?
n = 80/100 x 20
n= 0.80 x 20
n = 16
So 16 is 80% of 20
part (16) = percent (80%) x whole (20)
n = p x w (variable representation