Prime Factorization:
Objective: To identify prime and composite numbers.
To write the prime factorization of numbers
Vocabulary
Prime Number: A number greater than 1 that has only two factors (1 and the number itself)
Examples: 5: because 5 and 1 are its only factors
17: because 17 and 1 are its only factors
Composite Number: A whole number greater than one that has more than two factors.
Examples: 6: because it has four factors 1, 2, 3, 6
9: because it has three factors 1, 3, 9
0 and 1 are neither prime or composite
Prime Factorization: A number written as a product of factors that are all prime numbers.
Factor Tree: A useful tool used to find prime factorization.
Example: Make a factor tree for the number 40
40
5 8
4 2
2 25 2
40
2 20
4 5
2 22 5
40
5 8
4 2
2 25 2
All three factor trees have three 2’s and a 5
The prime factorization of 40 is 523
50
2 25
5 52 2•52
120
1012
4 3 5 2
2 2 3 5 2
23•3•5