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Sally has 5 red cards, numbered 1, 2, 3, 4 and 5, and 4 blue cards, numbered 3, 4, 5 and 6.
Can you find a way in which Sally can line the cards up so that the colours alternate, and so that the number on each red card is a factor of every number next to it?
This problem is adapted from the World Mathematics Championships
Red Card Blue Card
Age 11 to 14
ShortChallenge Level 
Sally has 5 red cards, numbered 1, 2, 3, 4 and 5, and 4 blue cards, numbered 3, 4, 5 and 6.
Can you find a way in which Sally can line the cards up so that the colours alternate, and so that the number on each red card is a factor of every number next to it?
This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.
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