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Factoring Numbers. Erica Matulich MTED 301 MW 8:00AM. Idea #1. “Factors” are the numbers you multiply to get another number. Idea #1. Example: Factors of 15 3 and 5 , because 3 x 5 = 15. Idea #1. Some numbers have more than one factorization. Idea #1. Example: 12 12= 1x 12.
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Factoring Numbers Erica Matulich MTED 301 MW 8:00AM
Idea #1 • “Factors” are the numbers you multiply to get another number.
Idea #1 Example: Factors of 15 3and 5, because 3 x 5= 15
Idea #1 • Some numbers have more than one factorization
Idea #1 • Example: 12 • 12= 1x 12
Idea #1 • Example: 12 • 12= 1x 12 • 12= 2 x 6
Idea #1 • Example: 12 • 12= 1x 12 • 12= 2 x 6 • 12= 3 x 4
Idea #2 • A number that can be factored as 1 times itself is called “prime”
Idea #2 • First few prime numbers are: 2,3,5,7,11,13
Idea #3 • You most often want to find the "prime factorization" of a number.
Idea #3 • Meaning: you want to find the list of all the prime-number factors of a given number.
Idea #3 • For instance, the prime factorization of 8 is 2×2×2, not just "2".
Idea #3 • Yes, 2 is the only factor, but you need three copies of it to multiply back to 8. 2 x 2 x 2 = 8
Idea #4 • Prime factorization includes ONLY the prime factors, not any products of those factors.
Idea #4 • Prime factorization includes ONLY the prime factors, not any products of those factors. • For example: 2×2 = 4
Idea #4 • Prime factorization includes ONLY the prime factors, not any products of those factors. • For example: 2×2 = 4 4 is a divisor of 8
Idea #4 • Prime factorization includes ONLY the prime factors, not any products of those factors. • For example: 2×2 = 4 4 is a divisor of 8 4 is NOT in the PRIME factorization of 8.
Idea #4 • Prime factorization includes ONLY the prime factors, not any products of those factors. • For example: 2×2 = 4 4 is a divisor of 8 4 is NOT in the PRIME factorization of 8. • That is because 8 does NOT equal2×2×2×4!
Idea #4 • Example: The number 24
Idea #4 24 / \ 2 12 / \ 26 / \ 23
Idea #4 2 x 2 x 2 x 3= 24
Idea #4 • Find the prime factorization of 1050
Idea #4 1050 / \ 2 525 / \ 3 175 / \ 5 35 / \ 5 7
Idea #4 Then the answer is: 1050 = 2 × 3 × 5 × 5 × 7
The End • Hope you learned something new and are excited to factor numbers!!