Question: what is the greatest common factor between 39 and 69?
Answer: The prime factorization of 69 is: 3 x 23.
The prime factorization of 39 is: 3 x 13.
The prime factors and multiplicities 69 and 39 have in common are: 3.
3 is the gcf of 69 and 39.
gcf(69,39) = 3.