Permutation relates to the act of arranging all the members of a set into some sequence or order. Combination is a way of selecting items from a collection, such that (unlike permutations) the order of selection does not matter.
The formulas to calculate the permutation of choosing r things from a set of n things is given to be:
The formula for calculating the combination choice of r things from a set of n things without replacement and where order does not matter is given to be:
An example of permutation is arranging people, digits, numbers, alphabets, letters, and colors. An example of combination is the selection of menu, food, clothes, subjects, and team.