You may also like

problem icon

Where Can We Visit?

Charlie and Abi put a counter on 42. They wondered if they could visit all the other numbers on their 1-100 board, moving the counter using just these two operations: x2 and -5. What do you think?

problem icon


Can you find the values at the vertices when you know the values on the edges?

problem icon

Gr8 Coach

Can you coach your rowing eight to win?

Charlie's Delightful Machine

Age 11 to 16 Challenge Level:

You could start by exploring Shifting Times Tables to get a feel for the sequences that turn on the lights.

Try exploring just one light at a time.