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23456


I am standing behind five pupils who are signalling a five-digit number to someone on the opposite side of the playground.

From where I am standing the number looks like 23456.
What number is actually being signalled?

 

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

 

 

This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.