My husband and I are trying to help one of our 7th graders w/her algebra homework and are experiencing senior moments. LOL

Any assistance would be appreciated in an explanation of finding the answers.
Thank you

Find the least common multiple of the monomials:
3S, S2(S squared)
X4 (X to the 4th power), X2( X squared)
15m2 (15m squared), 9m
8b, 20b2(20b squared)