Question: what are the greatest common factors for 49 and 14?
Answer: The factors of 14 are 14, 7, 2, 1. The factors of 49 are 49, 7, 1. The common factors of 14 and 49 are 7, 1, intersecting the two sets above. In the intersection factors of 14 ∩ factors of 49 the greatest element is 7. Therefore, the greatest common factor of 14 and 49 is 7.