Prime and Composite Numbers Mrs. Large 5th Grade Math

Review and Build Background Product Factor Prime Number Composite Number

Product An answer to a multiplication problem. 7 x 8 = 56 Product

Factor A number that is multiplied by another to give a product. 7 x 8 = 56 Factors

What are the factors? 6 x 7 = 42 6 & 7 7 x 9 = 63 7 & 9 8 x 6 = 48 8 & 6 4 & 9 4 x 9 = 36

What are the factors? 42 ÷ 7 = 6 7 63 ÷ 9 = 7 9 48 ÷ 6 = 8 6 9 36 ÷ 9 = 4

We talked about prime numbers earlier this year. What is a prime number? We talked about prime numbers earlier this year.

7 Prime Number A number that has only two factors, itself and 1. 7 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 One is not a prime nor a composite number. It is not prime because it does not have exactly two different factors. It is not composite because it does not have more than 2 factors. Special Note: One is not a prime nor a composite number.

8 Composite number The factors of 8 are 1, 2, 4, 8 A number that has more than two factors. 8 The 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 Let’s Practice With A Partner 1. 76 prime composite 2. 88 prime composite 3. 17 prime composite 4. 39 prime composite 5. 57 prime composite 6. 82 prime composite 7. 21 prime composite 8. 2 prime composite 9. 60 prime composite 10. 99 prime composite

Prime Card Game You will play in small groups of 4/5. Divide each deck of cards evenly among members. Place cards face down in stack in front of you. All group members turn one card up at the same time. If you have a prime number, you say “prime”. The first person to say “prime” wins the pile of cards. 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