What does P mean in Maths?

Answer 1

Many times in math the same letter or symbol may be used to annotate different things. As an example:

• P is used in statistics to denote Probability.
  For instance P("a single coin flip turns out to be head") = 1/2
• P may be used as a general name for a Polynomial
  For instance P1(x)=x2 ; P2(x)=2x+x3

Answer 2

P = Plus

M = Minus

F = Fraction