the factors of 18 is 1,18,2,9,3 and 6.
http://wiki.answers.com/Q/What_is_the_factor_of_18

1 and 3.
http://wiki.answers.com/Q/What_are_the_common_fact...

Factors of 18 are 1, 2, 3, 6, 9, and 18. Factors of 42 are 1, 2, 3, 6, 7, 14, 21, and 42. The common factors of 18 and 42 are 1, 2, 3, and 6.
http://wiki.answers.com/Q/What+common+factors+of+1...

Common factors of 18 and 24 are: 1, 2, 3, and 6.
http://wiki.answers.com/Q/What_are_common_factors_...
