Is zero a natural number?

[Jehanne]

Depends a bit on the book used.  One way of resolving ambiguities is as follows:

Positive: >0
Negative: <0
Non-negative: >=0
Non-positive: <=0

So, 0 is not negative, not positive, but is non-negative and non-positive.

Well that's just double talk. Don't even try to tell me about swamp land in Florida.

I suppose next you'll tell me that infinity exists between 0 and 1.

Between 0 and 1, there exists an infinitude of numbers, some of which are countable (the rational) and others that are not countable (the reals, complex and surreals).