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Joined: 30 Jan 2018
Posts: 4

Re: Which of the following numbers is prime?
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09 Apr 2018, 09:23
117 is divisible by 3, as 1+1+7 = 9 133 is divisible by 7, as 1407 = 133 189 is divisible by 3, as 1+8+9 = 18 209 is divisible by 11, as 22011 = 209
So therefore I think that 223 is prime (E)
