5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
1. 6, ?59 is divisible by 3.
2. 6, 1?0 is divisible by 4.
3. 6, ?52 is divisible by 6.
4. 6, 15? is divisible by 9.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
1. 6, ?59 is divisible by 3.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
1. 6, ?59 is divisible by 3.
6 + 5 + 9 = 20, 2 + 0 = 2
The missing digit can be either 1, 4, or 7.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
2. 6, 1?0 is divisible by 4.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
2. 6, 1?0 is divisible by 4.
The missing digit can be 2, 4, 6, 8, or 0.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
3. 6, ?52 is divisible by 6.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
3. 6, ?52 is divisible by 6.
6 + 5 + 2 = 13. 1 + 3 = 4
Since the last digit is even, it is divisible by 2.
To make it divisible by 3 the missing digit can be either 2, 5, or 8.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
4. 6, 15? is divisible by 9.

5 Minute Check
Determine the missing digit to make the statement true. Complete on the back of your homework.
4. 6, 15? is divisible by 9.
6 + 1 + 5 = 12, 1 + 2 = 3
So the missing digit can only be 6.

Prime Factors
Video

Wednesday, Aug 26
Review Lesson 5
Prime Factors

Prime Factors
Objective: To reduce composite numbers to prime factors.

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

Prime Factors
The factors of a number can be found be creating a factor rainbow.
20: 1, 2, 4, 5, 10, 20

Prime Factors
What are the factors of 32?
(Hint – create a factor rainbow)

Prime Factors
What are the factors of 32?
32: 1, 2, 4, 8, 16, 32

Prime Factors
What are the factors of 32?
32: 1, 2, 4, 8, 16, 32
How many factors do we have?

Prime Factors
What are the factors of 32?
32: 1, 2, 4, 8, 16, 32
How many factors do we have? 6

Prime Factors
All numbers have an even number of factors except for which special numbers?

Prime Factors
Numbers which have two of the same factors that have an odd number of factors.
16: 1, 2, 4, 8, 16
How many factors do we have?

Prime Factors
4 squared, or more commonly written 4² is
4 x 4, or 16.
The square root of 16 would be two of the same numbers we can multiply together to get 16, which would be 4.
What is the square root of 25?

Prime Factors
The square root of 25 is 5, because 5 x 5 =
25.
This is written as √ 25 = 5

Prime Factors
What are the factors of 47?

Prime Factors
What are the factors of 47?
47: 1, 47
A number that has only two factors is called what?

Prime Factors
A prime number is a number that only has 2 factors. example -
1 x 7 = 7 (prime number)
The factors of 7 are 1 and 7
1 x 6 = 6 and 2 x 3 = 6 (not a prime number)
The factors of 6 are 1,2,3,6

Prime Factors
A number that has more than two factors is called a what?

Prime Factors
A whole number, greater than 1, that has more than 2 factors is a composite number. example -
1 x 7 = 7 (prime number)
The factors of 7 are 1 and 7
1 x 6 = 6 and 2 x 3 = 6 (composite number)
The factors of 6 are 1,2,3,6

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

Prime Factors
Is 27 a prime or composite number?
27: 1, 3, 9, 27
27 is a composite number because it has more than two factors.

Prime Factors
I s 82 a prime or composite number?

Prime Factors
I s 82 a prime or composite number?
82: 1, 2, 41, 82
82 is a composite number because it has more than two factors.

Prime Factors
What is the only prime number that is even?

Prime Factors
What is the only prime number that is even?
2

Prime Factors
Is 53 a prime or composite number?

Prime Factors
Is 53 a prime or composite number?
53: 1, 53
53 is a prime number because it only has two factors.

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

Prime Factors
Find the prime factors of 18.
What prime numbers can we multiply together to get 18?

Prime Factors
Find the prime factors of 18.
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.
What is the smallest prime number?

Prime Factors
Find the prime factors of 18.
Is 18 divisible by 2?

Prime Factors
Find the prime factors of 18.
18
/ \
2 x 9
Circle any prime numbers.

Prime Factors
Find the prime factors of 18.
Is 9 divisible by 2? 18
/ \
2 x 9

Prime Factors
Find the prime factors of 18.
Is 9 divisible by 2? 18
/ \
2 x 9
No, so we move to the next smallest prime number. What is that?

Prime Factors
Find the prime factors of 18.
Is 9 divisible by 3? 18
/ \
2 x 9

Prime Factors
Find the prime factors of 18.
18
/ \
2 x 9
1 / \
2 x 3 x 3
We are done because we have all prime numbers.

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

Prime Factors
Find the prime factors of 54.
Is 54 divisible by 2?
54
/ \
2 x 27

Prime Factors
Find the prime factors of 54.
Is 27 divisible by 2?
54
/ \
2 x 27

Prime Factors
Find the prime factors of 54.
Is 27 divisible by 2?
54
/ \
2 x 27
No, so we move to the next smallest prime number. What is that?

Prime Factors
Find the prime factors of 54.
Is 27 divisible by 3?
54
/ \
2 x 27

Prime Factors
Find the prime factors of 54.
54
/ \
2 x 27
I / \
2 x 3 x 9

Prime Factors
Find the prime factors of 54.
Is 9 divisible by 3?
54
/ \
2 x 27
I / \
2 x 3 x 9

Prime Factors
Find the prime factors of 54.
Is 9 divisible by 3?
54
/ \
2 x 27
I / \
2 x 3 x 9
I I / \
2 x 3 x 3 x 3
The prime factors of 54 are 2 x 3 x 3 x 3, or 2 x 3 3

Prime Factors
Find the prime factors of 28.
Do this on your own.

Prime Factors
Find the prime factors of 28.
28
/ \
2 x 14
I / \
2 x 2 x 7
The prime factors of 28 are 2 x 2 x 7, or 2² x 7

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

Prime Factors
Find the prime factors of 30.
30
/ \
2 x 15
I / \
2 x 3 x 5
The prime factors of 30 are 2 x 3 x 5

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

Prime Factors
Find the prime factors of 43.
43 is a prime number, only composite number can be reduced to prime factors.

Prime Factors
Find the prime factors of 32.
Do this on your own.

Prime Factors
Find the prime factors of 32.
32
/ \
2 x 16
I / \
2 x 2 x 8
I I / \
2 x 2 x 2 x 4
I I I / \
2 x 2 x 2 x 2 x 2
The prime factors of 32 are 2 x 2 x 2 x 2 x 2, or 2 5

Prime Factors
Find the prime factors of 49.
Do this on your own.

Prime Factors
Find the prime factors of 49.
49
/ \
7 7
The prime factors of 49 are 7 x 7, or 7²

Prime Factors
Agenda Notes
Homework –
Homework Practice R.5
Due Thursday, Aug 27