least common include both so
factor and include all
5c=5 times c=at least one 5 and at least one c
6c^2=2 times 3 time c times c= at least one 2, at least one 3, at least 2 c's
include all
at least one 2, at least one 3, at least one 5 at least two c's
2 times 3itm es 5itmes c time sc=30c^2
