An [[Integer]] is an element in the [[Infinite Set|Countable Set]] of all [[Integer|integers]], $\Z$, which includes all positive and negative non fractional [[Real Numbers|real numbers]]. $\huge \Z = \setbuild{x \in \R }{ \lfloor x \rfloor = x } $ This [[Set]] can also be thought of being a union between $0$, [[Natural Numbers]], and the negative of each [[Natural Numbers|Natural Number]] $\huge \Z = \set{0} \cup \N \cup \setbuild{x \in \N}{-x} $