1. 5 Minute Check Complete in your notebook.
Tell whether each number is divisible by 2,3,4,5,6,9,10.
1. 80
2. 81
3. 93
4. 324
5. 24,681

2. 5 Minute Check Complete in your notebook.
Tell whether each number is divisible by 2,3,4,5,6,9,10.
1. 80 – 2, 4, 5, 10
2. 81
3. 93
4. 324
5. 24,681

3. 5 Minute Check Complete in your notebook.
Tell whether each number is divisible by 2,3,4,5,6,9,10.
1. 80 – 2, 4, 5, 10
2. 81 – 3, 9
3. 93
4. 324
5. 24,681

4. 5 Minute Check Complete in your notebook.
Tell whether each number is divisible by 2,3,4,5,6,9,10.
1. 80 – 2, 4, 5, 10
2. 81 – 3, 9
3. 93 – 3
4. 324
5. 24,681

5. 5 Minute Check Complete in your notebook.
Tell whether each number is divisible by 2,3,4,5,6,9,10.
1. 80 – 2, 4, 5, 10
2. 81 – 3, 9
3. 93 – 3
– 2, 3, 4, 6, 9
5. 24,681

6. 5 Minute Check Complete in your notebook.
Tell whether each number is divisible by 2,3,4,5,6,9,10.
1. 80 – 2, 4, 5, 10
2. 81 – 3, 9
3. 93 – 3
– 2, 3, 4, 6, 9
5. 24,

7. Wednesday, August 28
Prime Factors

8. Prime Factors When two or more numbers are multiplied,
each number is called a factor of the product.
example -
1 X 7 = 7 The factors of 7 are 1 and 7
1 X 6 = 6 and 2 X 3 = 6
The factors of 6 are 1,2,3,6

9. Prime Factors
If a number has only two factors (1 and itself) it is a prime number.
example -
1 X 7 = 7 The factors of 7 are 1 and 7
This is a prime number
1 X 6 = 6 and 2 X 3 = 6
The factors of 6 are 1,2,3,6
This is not a prime number

10. Prime Factors
If a number (greater than 1) has more than 2 factors it is a composite number.
example -
1 X 7 = 7 The factors of 7 are 1 and 7
This is not a composite number
1 X 6 = 6 and 2 X 3 = 6
The factors of 6 are 1,2,3,6
This is a composite number

11. Prime Factors
We can make factor list (factor rainbow) to determine if a number is prime or composite.
A multiples list will list all factors of a number, not just prime factors.

12. Prime Factors
Is 27 a prime or composite number? (Hint- think about the divisibility rules.)

13. Prime Factors
Is 27 a prime or composite number? Factor List 27: 1, 3, 9, is a composite number.

14. Prime Factors
Is 82 a prime or composite number?

15. Prime Factors
Is 82 a prime or composite number? Factor List 82: 1, 2, 41, is a composite number.

16. Prime Factors
Rule – only one even number is a prime number. All others are composite.
What is the only even number that is prime?

17. Prime Factors
Rule – only one even number is a prime number. All others are composite.
What is the only even number that is prime?
2, the only factors are 1 and 2.

18. Prime Factors
Is 47 a prime or composite number?

19. Prime Factors
Is 47 a prime or composite number? Factor List 47: 1, is a prime number.

20. Prime Factors
Every composite number can be expressed as a product of factors that are prime numbers. This is called prime factorization of the number. A factor tree can be used to find the prime factorization of a composite number.

21. Prime Factors
In a factor tree we “factor out” (divide by) prime numbers. We start with the smallest prime number and keep dividing until it is not divisible.

22. Prime Factors
Find the prime factorization of 45. What is the smallest prime number?

23. Prime Factors
Find the prime factorization of 45. Is 45 divisible by 2?

24. Prime Factors
Find the prime factorization of 45. Is 45 divisible by 2? No. What is the next smallest prime number?

25. Prime Factors
Find the prime factorization of 45. Is 45 divisible by 2? No. Is 45 divisible by 3?

26. Prime Factors
Yes, 45 ÷ 3 = / \ 3 X 15 We keep dividing by 3 until it is not divisible. Is 15 divisible by 3?

27. Prime Factors
Yes, 15 ÷ 3 = 5 45 / \ 3 X 15 I / \ 3 X 3 X 5 Since we have all prime numbers, we are done. The prime factorization of 45 is 3 X 3 X 5, or 3² X 5.

28. Prime Factors
Factor Tree Rule – Prime numbers have one “root” and composite numbers have two “roots”. 45 roots / \ roots 3 X 15 I / \ 3 X 3 X 5

29. Prime Factors
Find the prime factorization of 54. Is 54 divisible by 2?

30. Prime Factors
Yes, 54 ÷ 2 = / \ 2 X 27 We keep dividing by 2 until it is not divisible. Is 27 divisible by 2?

31. Prime Factors
No, we are done dividing by / \ 2 X 27 What is the next greatest prime number?

32. Prime Factors
Is 27 divisible by 3? 54 / \ 2 X 27

33. Prime Factors
Yes, 27 ÷ 3 = 9 54 / \ 2 X 27 I / \ 2 X 3 X 9 Is 9 divisible by 3?

34. Prime Factors
Yes, 9 ÷ 3 = 3 54 / \ 2 X 27 I / \ 2 X 3 X 9 I I / \ 2 X 3 X 3 X 3 Once we have all prime numbers, we are done. The prime factorization of 54 is 2 X 3 X 3 X 3, or 2 X 3³.

35. Prime Factors
Find the prime factorization of 20. Do this on your own.

36. Prime Factors
Find the prime factorization of / \ 2 X 10 I / \ 2 X 2 X 5 The prime factorization of 20 is 2 X 2 X 5, or 2² X 5

37. Prime Factors
Find the prime factorization of 30. Do this on your own.

38. Prime Factors
Find the prime factorization of / \ 2 X 15 I / \ 2 X 3 X 5 The prime factorization of 30 is 2 X 3 X 5

39. Prime Factors
Find the prime factorization of 43. Do this on your own.

40. Prime Factors
Find the prime factorization of is a prime number.

41. Prime Factors
Find the prime factorization of 104. Do this on your own.

42. Prime Factors
Find the prime factorization of 104.
104
/ \
2 X 52
I / \
2 X 2 X 26
I I / \
2 X 2 X 2 X 13
The prime factorization of 104 is 2 X 2 X 2 X 13, or 2³ X 13

43. Prime Factors
Agenda Notes- Math Homework Practice Skills 1-3 Due Quiz on Friday, Aug 30

44. Prime Factors