# Combinatorics

In Real life, we come across many situations, where we need to decide on combinations of certain things, may be or may not be with certain constraints. For example, choosing different fruits like apple, banana or grapes, to make fruit salad, or the safe key lock with a certain number code, which unlocks only with the correct digit combination, or at a restaurant choosing the appetizers, courses, deserts for a dinner party, or in how many ways can we set 9 books in a shelf and so on.

Such problems which are based on combinations and permutations are dealt in detail in the branch of Mathematics, called Combinatorics.

The study of Combinatorics roots from long times in B.C., starting from Mathematicians like Mahavira, Pingala, Plutarch, Abraham ibn Ezra, 13th Century legends like Leonardo Fibonacci, Jordanus de Nemore, to 17th/18th Century Pascal, Leibnitz, and Euler. George Polya, a Hungarian Analyst, one among the many famous Mathematicians, also worked on Combinatorics in the beginning of 19th century.