Basic question about Factors and Multiples:
When we define factors as
For an integer $x$, any integer which is completely divisible by $x$ is a factor of $x$.
and multiples as
For an integer $y$, any integer $z$ whose product with $y$ is an integer (or is it whole number? I am confused :s) is a multiple of $y$.
are we talking about negative integers and $0$ as well? or are we just talking about the positive integers or just whole numbers or just natural numbers? I am confused here.
I mean are there negative factors and multiples as well? and what about $0$?
PS: Please tweak my definitions if you find a mistake in them, but please keep the jargon simple if you do so. Thank you.