1. Prime and Composite Numbers
Grade 5 Lesson 1.6
Prime and Composite Numbers

2. How can I show factors? arrays 1 by 4 2 by 2 4 by 1 1 2 4 4 1 2 4 ….
. .. .
Dot Arrays
arrays 1 by 4 2 by 2 4 by
1 by 10
2 by 5
5 by 2
10 by 1 10
Factor Rainbows
Factor Trees

3. What is Prime?
A prime number is any number that can be represented by exactly 2 factors. 1 and itself. The number 2 is prime. What about the number 4?

4. Composite
A composite number is a number greater than 1 and has more than two factors. The number 1 is considered neither prime nor composite. This is a mathematical convention – something that has been agreed upon by mathematicians.

5. Workbook page 16
Please complete Workbook page 16. You may work with a partner if you want to. Note if each number is (P) Prime or ( C ) Composite.

6. Factor Captor
With a partner & your math workbook on page 17. You may also like your Student Reference Book on page 306. Determine the best 3 moves for a game of Factor Captor.

7. Partner activity
Complete workbook page 18 with a partner; number-line patterns. Homework: Page 17 is homework: Find the factors of whole numbers and identify numbers as prime or composite.

8. Enrichment
Goldbach’s Conjecture Christian Goldback ( ) had a theory – every even number greater than 2 can be written as the sum of two prime numbers. Rename each whole number (workbook page 19) as a sum of two prime numbers. Was he right? Why or Why not? (Write your answers in your ISN’s)