| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Additional Mathematics |
| Lesson Topic: Know and use the notation n! and the standard expressions for permutations and combinations of n items taken r at a time |
Learning Objective/s:
- Describe factorial notation and compute n! for given values.
- Explain the formulas for permutations and combinations and when each is appropriate.
- Apply the permutation and combination formulas to solve selection and arrangement problems.
- Distinguish between ordered and unordered selections and avoid common errors.
|
Materials Needed:
- Projector or interactive whiteboard
- Printed worksheet with practice questions
- Calculator (or scientific calculator app)
- Set of index cards for hands‑on grouping activity
- Whiteboard markers and erasers
|
Introduction:
Begin with a quick mental‑math challenge: ask students how many ways they could arrange four different books on a shelf. Recall that they have already learned multiplication sequences and the concept that 0! = 1, linking to factorials. Explain that by the end of the lesson they will be able to write and use the n! notation and the standard permutation and combination formulas.
|
Lesson Structure:
- Do‑now (5′) – mental‑math task on arranging books; students write answer on a sticky note.
- Direct instruction (10′) – introduce factorial notation, demonstrate with 5! and 0!.
- Guided practice (12′) – work through the permutation formula using {}⁸P₃; students solve a similar problem in pairs.
- Interactive activity (10′) – use index cards to form groups, then convert to combinations; discuss the relationship {}ⁿPᵣ = {}ⁿCᵣ × r!.
- Independent practice (8′) – worksheet with four mixed permutation/combination questions; teacher circulates to check understanding.
|
Conclusion:
Summarise that factorials underpin both permutations and combinations and review the key formulas. Students complete an exit ticket by writing one example of a permutation and one of a combination from today’s lesson. Assign homework: two additional textbook problems covering both concepts.
|