Permutation : means various possible ways to arrange or order a set or number of things. Meaning of permutation comes from the word permuting which means rearranging objects or values. Example : there are 6 permutations possible for set {1,2,3}. That is (1,2,3), (1,3,2), (2,1,3), (2,3,1), (3,1,2), (3,2,1). Combination doesn't care about the order, t just says what is the combination of the objects. Formulae for permutations of n different objects is n! (n factorial). Permuntations and combinations is a part of arithmetic questions which are frequently asked in many interviews. This section contains questions and answers on permutations and combinations.