Learn how to calculate the number of permutations of r items from a set of n items using the nPr formula. See the formula derivation, solved examples and a list of maths formulas on one page. Permutation refers to arranging or ordering a set of distinct elements in a specific sequence. It involves rearranging the elements in every possible way, without repetition, to generate distinct permutations. The total number of permutations for a set of ' n n ' elements is given by n n factorial (n! n!). In this maths formula article, we will learn the Permutation Formula along with some solved examples of permutation formulas. Given two numbers, n and r, the task is to compute nPr, which represents the number of ways to arrange r elements from a set of n elements. It is calculated using the formula n!/ (n−r)!, where "!" denotes the factorial operation. The formula for nPr is given by $$ nPr = \frac {n!} { (n-r)!} $$, which shows how permutations depend on both the total number of objects and the number selected.
