Permutations are used in almost every branch of mathematics and in many other fields of science. In computer science, they are used for analyzing sorting algorithms; in quantum physics, for describing states of particles; and in biology, for describing RNA sequences.

So, in Mathematics we use more precise language: When the order doesn't matter, it is a Combination. When the order does matter it is a Permutation.

Sep 17, 2023 · Find the number of ways of getting an ordered subset of r elements from a set of n elements as nPr (or nPk).

4 days ago · In Mathematics, Permutation is defined as a mathematical concept that determines the number of possible arrangements for a specific set of elements. therefore, it plays a big role in computer science, cryptography, and operations research.

Permutations and combinations, the various ways in which objects from a set may be selected, generally without replacement, to form subsets. This selection of subsets is called a permutation when the order of selection is a factor, a combination when order is not a factor.

A permutation refers to a selection of objects from a set of objects in which order matters. A phone number is an example of a ten number permutation; it is drawn from the set of the integers 0-9, and the order in which they are arranged in matters.

Permutation means "both selection and arrangement" whereas combination means just the "selection". Wherever the ordering of objects does not matter, we use combinations there.