I need an way to remember the set operations very easily.
Does anybody have any idea?
For example, how do you remember the distinction between Set-Intersection and Set-difference? I regularly mess it up.
[Math] How to remember various set operations very easily
adviceelementary-set-theorynotation
Best Answer
As 5xum mentioned in the comments, union starts with a u and has a symbol $\cup$ that looks very much like a $u$. Then intersection is simply the same symbol flipped $\cap$.
As for what they mean, you can think of union $A \cup B$ as a cup (indeed, the LaTeX command for it is
\cup) in which you pour all of the elements of both $A$ and $B$, whereas $A \cap B$ has two legs, one in $A$ and one in $B$, so it contains only those elements that are in both $A$ and $B$.