Ch. 4.2
Factors and Prime Factorization
Factors: whole numbers that are multiplied to find a product are factors of that product.
Ex. 2 x 3 = 6
2 and 3 are the factors, 6 is the product
Listing Factors of a number:
1. List in pairs or by the “rainbow method”
Ex. Factors of 18:
or…
1, 18
2, 9
3, 6
1, 2, 3, 6, 9, 18
Prime Factorization: the number written as the product of its prime factors. (can be written different
ways)
Steps:
1. Use a tree diagram
2. Break the number down by its factors until you have all primes
3. Circle the primes
Ex. Prime Factorization of 20
20
So… 22 x 5 is the prime factorization
5
4
2
2
…here is another way you could have ‘broken down’ 20
20
So… 22 x 5 is still the prime factorization
2
10
5
2