Lesson Plan for Factorial and Permutations - Math 11

Topic: Introduction to Factorial and Permutations

Materials: 20 whiteboard markers, 4 erasers

Audience: Teacher Candidates in Math Pedagogy Class (Grade 11 Pre-Calc Material)

Overall Learning Objective: Learn to calculate permutations of objects

Objectives & Topics	Activities	Assessments	Time (15 min)
Motivate ideas of permutation of objects	Get into groups of 4; how many ways can you arrange yourselves? Introduce term “Permutation” (certain number of unique objects, order matters)	Have groups tabulate arrangements, look for duplicates or missing arrangements and confusion	2-4 min
Give students the chance to connect different arrangements and calculate how many are possible	Make connection between chair arrangements and distribution of markers. How many possibilities are there if we have 2/3/4 markers to distribute to 2/3/4 people?	Students will tabulate results using a table. Watch for duplicates, confusion, frustration. See if students are noticing a pattern	5-7 min
Transition from counting solutions	What is the pattern? How would is each number related to the one before? How would you find the number of permutations for 5 objects? Show two ways of understanding the pattern.	Take answers from students. Ask leading questions about 6 or 7 markers to ensure understanding.	3-4 min
Introduce formal notation for factorial	Introduce factorial “!” and what it means. How big is 10! compared to 5! ?	Students can evaluate a factorial expression.	1-2 min
Give idea of how fast factorial grows and why combination problems get really tough to solve	Close: How long would it take to rearrange a 30 person class?	N/A	Remaining time