Question: what is the greatest common factor in 7 and 35?
Answer: The factors of 7 are 7, 1., The factors of 35 are 35, 7, 5, 1., The common factors of 7 and 35 are 7, 1, intersecting the two sets above., In the intersection factors of 7 ∩ factors of 35 the greatest element is 7., Therefore, the greatest common factor of 7 and 35 is 7.