Natural number: 0, 1, 2, 3, 4, 5, etc. Integer: negative natural
numbers Rational number: anything expressible as a ratio of two
integers, ie fractions, etc. (except when zero is in the
denominator-that isn't a rational number). Question: are there
more integers than natural numbers? Question: are there more
rational numbers than natural numbers? "Be as wise as a serpent
and as innocent as a dove."