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Peter's Primes

Age 14 to 16 Short
Challenge Level

Answer: None of them are prime


2  0 __
2 __ 0 none prime
__ 0 0 none prime

201: 2+1=3 multiple of 3
203: 203$\div$7 = 29
207: multiple of 3
209: not 7 again since too close to 209. 209$\div$11 = 19

None are prime



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