Probability is a branch of mathematics that deals with the occurrence of a random event. It is a measure of the likelihood of an event to occur, expressed as a number between 0 and 1, where 0 indicates impossibility of the event and 1 indicates certainty. Probability has been introduced in mathematics to predict how likely events are to happen. Whenever we are unsure about the outcome of an event, we can talk about the probabilities of certain outcomes, how likely they are.

To find the probability of a single event to occur, we should first know the total number of possible outcomes. The probability formula is defined as the possibility of an event to happen is equal to the ratio of the number of favorable outcomes and the total number of outcomes. The probability of an event can only be between 0 and 1 and can also be written as a percentage.

There are two types of probability: theoretical probability and empirical probability. Theoretical probability is used when dealing with random experiments in a purely theoretical setting, like tossing a coin. Probabilities can be numerically described by the number of desired outcomes, divided by the total number of all outcomes. Empirical probability deals with probabilities in the context of real experiments.

Probability is used in many fields, including science, engineering, finance, and social sciences. It is a fundamental concept in statistics, which is the analysis of events governed by probability.