Probability
Probability describes how likely something is to happen and can be mathematically calculated. Equations for calculating the probability of A (P(A)), are as follows:
P(A) = (# of ways A can happen) / (Total number of possible outcomes)
For example, what is the probability of getting heads when flipping a coin?
P(getting a head when flipping a coin) = 1 (heads) / 2 (heads or tails) = 1/2 or 50%
Another example, is what is the probability of rolling a 1 or 4 with a 6-sided die?
P(rolling a 1 or a 4) = 2 (values of 1 or 4) / 6 (total possible values) = 2/6 or 33%