Factors, Primes & Composite Numbers

1. Factors, Primes & Composite Numbers

2. Learning Objective: Today factor numbers and determine if they are prime or composite.

3. What will we learn today? Today we will factor numbers and determine if they are prime or composite.

4. Partner Share • What is 3 x 7? • What is the answer to a multiplication problem called?

5. Definition • Product – An answer to a multiplication problem. 7 x 8 = 56 Product

6. Definition • Factor – a number that is multiplied by another to give a product. 7 x 8 = 56 Factors

7. What are the factors?(What two numbers make that product?) 6 x 7 = 42 6 & 7 7 x 9 = 63 7 & 9 8 x 6 = 48 8 & 6 4 & 9 4 x 9 = 36

8. Definition • Prime Number – a number that has only two factors, itself and 1. 7 7 is prime because the only numbers that will divide into it evenly are 1 and 7.

9. Examples of Prime Numbers 2, 3, 5, 7, 11, 13, 17, 19 Special Note: One is not a prime number.

10. Definition • Composite number – a number that has more than two factors. 8 The factors of 8 are 1, 2, 4, 8 because 1x8=8 and 2x4=8

11. 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.

12. Our Lonely 1 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.

13. Why is it important to understand?

14. How to use a factor tree • 48 Step 1 – Write down two factors. (What two numbers make 48?)

15. How to use a factor tree Step 2 – Find factors of these numbers until all factors are prime. (what makes a 6? What makes an 8?) • 48

16. How to use a factor tree Step 2– Find factors of these numbers until all factors are prime numbers.

17. How to use a Factor Tree Step 3– Write the numbers from least to greatest. Determine if the number is prime or composite. Factors of 48 are: 1,2,3,4,6,8,48 Hint: only write each digit once. Composite

18. Step 1– Write down two factors. Step 2 – Find factors of these numbers until all factors are prime Step 3 – Write the numbers from least to greatest. Determine if the number is prime or composite. Factor this number Composite Factors of 6 are: Hint: only write each digit once. 1,2,4,6

19. Step 1– Write down two factors. Step 2 – Find factors of these numbers until all factors are prime Step 3 – Write the numbers from least to greatest. Determine if the number is prime or composite. Factor this number • 8 Composite Factors of 8 are: Hint: only write each digit once. 1,2,4,8

20. Factor this number Composite Factors of 6 are: Hint: only write each digit once. 1,2,5,10

21. Factor this number • 20 Composite Factors of 8 are: Hint: only write each digit once. 1,2,4,5,20

22. Factor this number Prime Factors of 7 are: 1,7 Hint: only write each digit once.

23. Factor this number Prime Factors of 13 are: 1,13 Hint: only write each digit once.

24. What did we learn to factor today? Why is it important? Now you try!Factor this number Prime or composite? Factors of ___ are: _____________ Hint: only write each digit once. Don’t forget 1 and itself!

25. Now you try!Factor this number Prime or composite? Factors of ___ are: _____________ Hint: only write each digit once. Don’t forget 1 and itself!

26. Now you try!Factor this number Prime or composite? Factors of ___ are: _____________ Hint: only write each digit once. Don’t forget 1 and itself!

27. Step 1 – Write down two factors. Step 2 – Find factors of these numbers until all factors are prime Step 3 – Write the numbers from least to greatest. Determine if the number is prime or composite. Prime or composite? Factor this number Factors of __________ are: Hint: only write each digit once. Don’t forget 1 and itself! Print this slide for use in whiteboards