Download Warm Up




What prime factorization is.
For example the prime factorization of
24 = 2•2•2•3
Today we will learn how to find the greatest
common factor of two quantities.


Greatest common factor or GCF is the largest
factor that the two numbers have in common.
For example, the greatest common factor of 12
and 18 is 6.
The way we find it is by using prime
factorization and circling common prime
factors.





Find the GCF of 24 and 32
Step 1: Find the prime factorization of each
number
24 = 2•2•2•3
32 = 2•2•2•2•2
Step 2: Circle common prime factors
Step 3: Multiply common factors
GCF = 2•2•2 = 8





Find the GCF of 72 and 48
Step 1: Find the prime factorization of each
number
72 = 2•2•2•3•3
48 = 2•2•2•2•3
Step 2: Circle common prime factors
Step 3: Multiply common factors
GCF = 2•2•2•3 = 24




Find the GCF of the following sets of numbers
A) 36, 48
B) 45, 24
C) 15, 32