Using the method of factoring each number into primes, what is the greatest common factor of 54 and 36?

1. Factor 54 into primes: 54 = 2 times 3 times 3 times 3. 2. Factor 36 into primes: 36 = 2 times 2 times 3 times 3. 3. The factors shared by both numbers are one 2 and two 3s, so multiply 2 times 3 times 3 to get 18. 4. Since the GCF is a factor of both numbers, 54 and 36 can be written as 18 times 3 and 18 times 2. _Source: OpenStax Elementary Algebra (CC BY 4.0), Ch 7 "Factoring", section 7.1 Greatest Common Factor and Factor by Grouping_