Question: what is the greatest common factor between 49 and 100?
Answer: The prime factorization of 49 is: 7 x 7.
The prime factorization of 100 is: 2 x 2 x 5 x 5.
The prime factors and multiplicities 49 and 100 have in common are: 1.
1 is the gcf of 49 and 100.
gcf(49,100) = 1.