Prime and Composite Numbers

Mrs. Large5th Grade Math

Review and Build Background

ProductFactor

Prime NumberComposite Number

Product

An answer to a multiplication problem.

7 x 8 = 56Product

Factor

A number that is multiplied by another to give a product.

7 x 8 = 56

Factors

What are the factors?

6 x 7 = 427 x 9 = 638 x 6 = 484 x 9 = 36

6 & 77 & 98 & 64 & 9

What are the factors?

42 ÷ 7 = 663 ÷ 9 = 748 ÷ 6 = 836 ÷ 9 = 4

7969

What is a prime number?

We talked about prime numbers earlier this year.

Prime Number

A number that has only two factors, itself and 1.

77 is prime because the only numbers

that will divide into it evenly are 1 and 7

Examples of Prime Numbers

2, 3, 5, 7, 11, 13, 17, 19

Special Note:One is not a prime number.

Our Lonely 1

Special Note:One is not a prime nor a composite number.

It is not primebecause it doesnot have exactly

two differentfactors.

It is not composite

because it doesnot have morethan 2 factors.

Composite number

A number that has more than two factors.

8The factors of 8 are 1, 2, 4, 8

Examples of Composite Numbers

4, 6, 8, 9, 10, 12, 14, 15

Special Note:Every whole number from 2 on is

either composite or prime.

Let’s Practice With A Partner

1. 76 prime composite 2. 88 prime composite3. 17 prime composite4. 39 prime composite5. 57 prime composite6. 82 prime composite7. 21 prime composite8. 2 prime composite9. 60 prime composite10. 99 prime composite

Prime Card Game

1. You will play in small groups of 4/5.2. Divide each deck of cards evenly among members.3. Place cards face down in stack in front of you.4. All group members turn one card up at the same

time.5. If you have a prime number, you say “prime”.6. The first person to say “prime” wins the pile of

cards.7. Continue until all cards are gone.

Independent Activity

• Complete the Explore: Primes and Composites Number Sheet

• Journal Entry: write and explain prime and composite numbers/how do you think you could use this?

Call Me Prime-ee

• http://www.youtube.com/watch?v=zMFdp7Ib7CA

• (Thank you Mrs. Clardy for the video link).

Where are we going with this?

• Connecting to future lessons: fractions in simplest form least common

multiple, least common denominator, greatest common factor