section 5.1 prime factorization and greatest common factor
TRANSCRIPT
Section 5.1
Prime Factorization
and
Greatest Common Factor
A prime number is a number that can only be divided by
only one and itself.
A composite number is a number greater than one that is not prime.
Prime or composite?37
prime51
composite
Prime or Composite?89
1. Prime
2. Composite
3. Both
4. Neither
1) Find the prime factorization of 84.84 = 4 • 21
= 2 • 2 • 3 • 7
= 22 • 3 • 7
2) Find the prime factorization of -210.
-210 = -1 • 210
= -1 • 30 • 7
= -1 • 6 • 5 • 7
= -1 • 2 • 3 • 5 • 7
3) Find the prime factorization of 45a2b3
45a2b3 = 9 • 5 • a • a • b • b • b
= 3 • 3 • 5 • a • a • b • b • b
= 32 • 5 • a • a • b • b • b
Write the variables without exponents.
What is the prime factorization of 48?
1. 3 16
2. 3 4 4
3. 2 2 3 4
4. 2 2 2 2 3
The Greatest Common Factor (GCF) of 2 or more numbers isthe largest number that can divide
into all of the numbers.
4) Find the GCF of 42 and 60.
Write the prime factorization of each number.
4) Find the GCF of 42 and 60.
What prime factors do the numbers have in common?
Multiply those numbers.
The GCF is 2 • 3 = 6
6 is the largest number that can go into 42 and 60!
42 = 2 • 3 • 760 = 2 • 2 • 3 • 5
5) Find the GCF of 40a2b and 48ab4.
40a2b = 2 • 2 • 2 • 5 • a • a • b48ab4 = 2 • 2 • 2 • 2 • 3 • a • b • b • b • b
What do they have in common?Multiply the factors together.
GCF = 8ab
What is the GCF of 48 and 64?
1. 2
2. 4
3. 8
4. 16
What is the GCF of?
• 36 and 60
• 28a and 35a2
• 45 and 75
Some to try:
• 8ab and 48a
• 28, 42, 56
• 50, 55, 60