Probability is a branch of mathematics that deals with calculating the likelihood of a given event’s occurrence, which is expressed as a number between 1 and 0. Since no other outcome is possible, It is 1/2 (or 50%) of either “head” or “tail”. In other words, the probability of “head” is 1 out of 2 outcomes and the probability of “tail” is also, 1 out of 2 outcomes. An event with a probability of 1 can be considered a certainty. Also an event with a probability of 0 can be considered an impossibility. A little paradoxical, in this theory applies precise calculations to quantify uncertain measures of random events.