I guess I really hadn't had a calculator out much, today Mac saw it and was immediately fascinated with it. He figured out it can add, multiply, etc. and was very interested in all the numbers it would come up with. It kept him busy for over a half an hour. Of course then Emily wanted a turn, she was as fascinated by it, but when asked how it works I told her she had to put the numbers in and ask it to do something, so she started talking to it!