CEMC Banner

Problem of the Week
Problem C
Colour by Numbers

Jessica is going to colour the hexagons in the tiling below. Each hexagon will be coloured with a single colour. If two hexagons share a side, then they will be coloured with a different colour. What is the fewest number of colours that Jessica can use to colour all the hexagons?

A tiling of 27 identical hexagons that looks like part of a honeycomb. There are six vertical columns of hexagons in the tiling and the tiling has a horizontal line of symmetry. The first, third, and fifth columns each have four hexagons. The remaining columns each have five hexagons.

Not printing this page? You can colour the hexagons on our interactive worksheet.