You may also like

problem icon


Draw a 'doodle' - a closed intersecting curve drawn without taking pencil from paper. What can you prove about the intersections?

problem icon

Russian Cubes

I want some cubes painted with three blue faces and three red faces. How many different cubes can be painted like that?

problem icon

N000ughty Thoughts

How many noughts are at the end of these giant numbers?


Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2

This one was a tough problem! Some of you started to spot patterns and suggested possible rules, but the patterns didn't continue. In fact, a general rule for this sequence is pretty hard to write down! One very useful way of recording the number of walks of up to eight steps was this:

Can you see how the diagram works? Could you continue it to find the number of ten-step walks?