Maths Extension 1 Year 11 - Module 4 - Lesson 2
Factorial Notation & Simple Arrangements
Name
Date
Class
1. Lesson focus
Factorial notation and arrangements. Factorial notation multiplies descending positive integers; repeated letters require division by their repetition factorials.
Success criteria
- Apply the lesson method accurately in a routine example.
- Show each algebraic or domain step and check the result.
- Explain why the method and restrictions fit the question.
2. Worked practice
2. Solve n!/(n−1)!=7 for positive integer n.
3. How many distinct arrangements of LEVEL are there?
3. Challenge
Solve n!=120 for positive integer n.
4. Multiple choice
How many distinct permutations of AAB are there?
A. 3!/2!=3
B. 3!=6
C. 2!=2
D. 1
Worked answer key
Compare each step with your working. Keep stated intervals, domains and restrictions in your final answer.
1. Evaluate 6!.
6×5×4×3×2×1=720.
2. Solve n!/(n−1)!=7 for positive integer n.
The quotient simplifies to n, so n=7.
3. How many distinct arrangements of LEVEL are there?
Five letters with two Ls and two Es: 5!/(2!2!)=120/4=30.
Challenge. Solve n!=120 for positive integer n.
5!=120, so n=5.
Multiple choice. How many distinct permutations of AAB are there?
Correct answer: A. There are three positions and the two As are indistinguishable, so divide 3! by 2!.
Want help with Worksheet - Factorial Notation & Simple Arrangements?
Tell us what you would like help with. Register interest; support details will be confirmed before enrolment.
Register interest →