Question: what is the least common factor of 60 and 6?
Answer: The prime factorization of 6 is: 2 x 3.
The prime factorization of 60 is: 2 x 2 x 3 x 5.
Eliminate the duplicate factors of the two lists, then multiply them once with the remaining factors of the lists to get lcm(6,6) = 60.