Take an outline map of the lower 48 U.S. states and four crayons. Can you shade in the map so that every state is a different color than each of its neighbors, without resorting to a fifth color? This ...

In 1852, botanist Francis Guthrie noticed something peculiar as he was coloring a map of counties in England. Despite the counties’ meandering shapes and varied configurations, four colors were all he ...

Australian National University provides funding as a member of The Conversation AU. Recently, as a community ambassador for ANU Student Equity, I took to a local secondary school to talk maths with a ...