The graph below contains five regions; is that the number of colors we need to fill them with so that adjacent regions are different colors?

This is a problem that cartographers face when coloring a map with many states or countries that share borders. We’d like to find the *minimum* number of colors necessary to distinguish between adjacent regions.

To see a way to color the graph above, keep reading. Or, jump to today’s challenge for a coloring problem of your own.