The difference between two [[Set|Sets]] $A,B$ is a [[Binary Operation]], denoted as $A-B$ or $A\setminus B$, is defined as the [[Set]] whose elements are inside $A$, and outside $B$. $\huge A\setminus B = \set{x \mid x\in A \wedge x \not\in B} $ This [[Operation]] is [[Associative]] but not [[Commutative]].