Question: what is a common factor between 11 and 42?
Answer: The gcf of 42 and 11 can be obtained like this: The factors of 42 are 42, 21, 14, 7, 6, 3, 2, 1. The factors of 11 are 11, 1. The common factors of 42 and 11 are 1, intersecting the two sets above.