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Factors and Primes
by 2July
Definition
• Product – the answer to a multiplication problem.
5 x 6 = 30Product
Definition
• Factors – whole numbers that can be multiplied to give a product.
5 x 6 = 30
Factors
Definition
• Factor – a number that divides evenly into another.
30 ÷ 6 = 5
Factor
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
Definition• Prime Number – a number that
has only two factors, itself and 1.
55 is prime because the only numbers
that will divide into it evenly are 1 and 5.
Examples of Prime Numbers
2, 3, 5, 7, 11, 13, 17, 19
Note: 1 is not a prime number.
Definition• Prime Factorization – A way to
write a number as the product of prime factors.
2 x 2 x 3 = 12or
2 x 3 = 122
How to Do Prime Factorization Using a Factor Tree
48Step 1 – Start with a number.
Step 2 – Write down a pair of factors that make this number.
6 x 8 = 48
How to Do Prime Factorization Using a Factor Tree
Step 3 – Find factors of these factors.
6 x 8 = 48
2 x 3 x 2 x 4 = 48
How to Do Prime Factorization Using a Factor Tree
Step 4 – Find factors of these numbersuntil all factors are prime numbers.
6 x 8 = 482 x 3 x 2 x 4 = 48
2 x 3 x 2 x 2 x 2 = 48
How to Do Prime Factorization Using a Factor Tree
Step 5 – Count how many numbers arethe same and write them in index form.
6 x 8 = 482 x 3 x 2 x 2 x 2 = 482 x 2 x 2 x 2 x 3 = 48 2 x 3 = 484
Prime factor this number
42 x 2
2 = 42
= 4
Prime factor this number
62 x 3 = 6
Prime factor this number
82 x 4
2 = 83
= 82 x 2 x 2 = 8
Prime factor this number
93 x 3 = 9
3 = 92
Prime factor this number
102 x 5 = 10
Prime factor this number
123 x 4
2 x 3 = 122
= 123 x 2 x 2 = 122 x 2 x 3 = 12
Prime factor this number
142 x 7 = 14
Prime factor this number
153 x 5 = 15
Prime factor this number
164 x 4
2 = 164
= 162 x 2 x 2 x 2 = 16
Prime factor this number
183 x 6
2 x 3 = 182
= 183 x 2 x 3 = 182 x 3 x 3 = 18
Prime factor this number
204 x 5
2 x 5 = 202
= 202 x 2 x 5 = 20
