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What's on the Back?

Age 11 to 14 Short
Challenge Level

Answer:
2 - odd
5 - divisible by 7
7 - greater than 100
12 - prime


Below, the numbers are connected to the properties they satisfy
 


7 and "prime" both have three lines, leaving only one possibility for their backs: 


5 is odd so 2 must be on the back of "odd": 




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