Question: what are the greatest common factor of 18 and 49?
Answer: The prime factorization of 18 is: 2 x 3 x 3.
The prime factorization of 49 is: 7 x 7.
The prime factors and multiplicities 18 and 49 have in common are: 1.
1 is the gcf of 18 and 49.
gcf(18,49) = 1.