Tell him that's a good start. Then encourage him to go deeper than just new names for the same kinds of numbers we already know and come up with a whole new ki

Tell him that's a good start. Then encourage him to go deeper than just new names for the same kinds of numbers we already know and come up with a whole new kind of number. E.g. http://www-cs-staff.stanford.edu/~uno/sn.html http://www-cs-staff.stanford.edu/~uno/sn.html That could get the discussion going on what a number really is and what sorts of things could be numbers if only the rules were a little different.