Permutation

By Karan Singh Bisht

|

Updated on 29 Apr 2025, 11:58 IST

In mathematics, permutation refers to the arrangement of objects in a specific order. Unlike combinations, where the order does not matter, permutations focus on different ways objects can be arranged.

Example: With three letters A, B, and C, the permutations are: ABC, ACB, BAC, BCA, CAB, and CBA.

Fill out the form for expert academic guidance
+91

Permutations are used in probability, computer science, cryptography, seating arrangements, passwords, and scheduling.

What is Permutation?

Permutation refers to the arrangement of objects in a specific order. When working with permutations, both the selection and the sequence of arrangement are important. In essence, the order in which items are arranged plays a crucial role. Simply put, a permutation is an ordered combination.

Unlock the full solution & master the concept
Get a detailed solution and exclusive access to our masterclass to ensure you never miss a concept

Permutation Formula

The general formula is:

P(n, r) = n! / (n βˆ’ r)!

Permutation

Loading PDF...

  • n = total number of objects
  • r = number selected
  • ! = factorial

Example: Arranging 3 books out of 5:

P(5,3) = 5! / 2! = 60

Ready to Test Your Skills?
Check Your Performance Today with our Free Mock Tests used by Toppers!
Take Free Test

Types of Permutations

1. Without Repetition

Use standard formula: P(n, r) = n! / (n βˆ’ r)!

Example: 4-digit PIN using 1-9: P(9,4) = 3024

2. With Repetition

cta3 image
create your own test
YOUR TOPIC, YOUR DIFFICULTY, YOUR PACE
start learning for free

Use: n! / (n1! Γ— n2! Γ— ...) where n1, n2... are repeating item counts.

Example: LEVEL β†’ 5! / (2! Γ— 2!) = 30

Difference Between Permutations and Combinations

FeaturePermutationCombination
Order MattersYesNo
Formulan! / (n - r)!n! / (r!(n - r)!)
ExampleArrange 5 books in 3 slotsChoose 3 books out of 5
Used InPINs, seatingsLottery, team selection

Real-Life Applications

  • Seating Arrangements: P(5,5) = 120
  • Password Generation: P(26,4) = 358,800
  • Lottery System: P(49,6) = 49! / 43!
Also Check
Associative Property
Centroid of a Triangle
Collinear Points
Commutative Property
Cos 0
Hypotenuse

Conclusion

Permutation helps solve real-life problems like generating passwords, arranging seats, and scheduling. It's essential in competitive exams, computer science, and probability studies.

Permutation FAQs

What is a permutation and example?

A permutation is an arrangement of objects in a specific order. Unlike combinations, the order of elements in permutations matters.

Example: The permutations of the letters A, B, and C include: ABC, ACB, BAC, BCA, CAB, and CBA. Each unique arrangement is counted as a different permutation.

What are the permutations of 1, 2, 3, 4?

The permutations of the digits 1, 2, 3, 4 are all the possible ways to arrange them in different orders. Since there are 4 digits, the number of permutations is:

4! = 4 Γ— 3 Γ— 2 Γ— 1 = 24

Here are some examples of the 24 permutations:

  • 1234
  • 1243
  • 1324
  • 1342
  • 1432
  • 4321

How many 3-digit numbers can be formed using 1-9?

P(9,3) = 504

What is the permutation of 5?

The permutation of 5 refers to the total number of ways to arrange 5 unique elements. This is calculated using factorial notation:

5! = 5 Γ— 4 Γ— 3 Γ— 2 Γ— 1 = 120

So, there are 120 permutations of 5 distinct items.

What is 7 permutation 2?

The expression 7 permutation 2 (written as P(7, 2)) means the number of ways to arrange 2 items out of 7 in order.

P(7, 2) = 7! / (7 - 2)! = 7 Γ— 6 = 42

So, there are 42 possible permutations when choosing and arranging 2 out of 7 items.

What are the 3 types of permutation?

The three main types of permutations are:

  1. Permutation without Repetition – No element is repeated. Example: Arranging 3 out of 5 different books.
  2. Permutation with Repetition – Elements can repeat. Example: Creating a 4-digit PIN using digits 0–9.
  3. Circular Permutation – Arrangements are made in a circle, like seating people around a table. Example: 5 people sitting around a round table has (5 - 1)! = 24 circular permutations.