A permutation is an arrangement of items in a specific order. For example, if you have three letters, A, B, and C, the different ways to arrange these letters are ABC, ACB, BAC, BCA, CAB, and CBA. The total number of permutations depends on how many items you have and is calculated using factorial notation. In mathematics, permutations are important in fields like combinatorics and probability. They help in solving problems related to arrangements and selections. Understanding permutations can also be useful in real-life situations, such as organizing events or creating schedules.