You can send them to me! My hubby needs books like that for his classroom.

Most likely, you would do better giving them away to a local school or charity. The amount of money you'll get from a second hand bookstore is nothing (and the local second hand store is picky about what they will accept). The feeling you'll get from donating them and making somebody else's day will be worth the extra $50 you'd have made by selling them... not to mention a whole heck of a lot less work.