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. 6: because it has four factors 1, 2, 3, 6 Examples: 9: because it has three factors 1, 3, 9

0 and 1 are neither prime or composite A number written as a product of factors that are all prime numbers. Prime Factorization: A useful tool used to find prime factorization. Factor Tree: Example: Make a factor tree for the number 40 40 40 40 2 20 5 8 5 8 4 5 4 2 4 2 2 2 2 2 5 5 2 2 2 5 2 2 All three factor trees have three 2’s and a 5 The prime factorization of 40 is

50 2 25 2 5 5 2•52 120 12 10 5 4 3 2 2 2 3 5 2 23•3•5