Sorting with Circles: Mastering Venn Diagrams

Imagine you are sorting a pile of numbers into two boxes. Box A holds multiples of 2. Box B holds multiples of 3. You pick up the number 6. Which box does it go in? It fits both — but you only have two separate boxes. This is the problem Venn diagrams solve beautifully. They give every element exactly the right home, even when it belongs to more than one group.