Hey,
I've got a 22 year old and an 18 year old senior in high school. You know what they hate? Have them show you their math book, find the chapter they are working on and make them actually "read" the lessons. (You can help.) The exlpanation is more than likely right in front of them but it's easier to have you do the homework for them. Don't get caught in the trap of doing the work. Help them do it.
Been there, done that,
Dan'l