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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?

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Arithmagons

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

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Babylon Numbers

Can you make a hypothesis to explain these ancient numbers?

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.