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John Conway proves that 91 is the smallest number which looks prime but isn't
John Conway proves that 91 is the smallest number which looks prime but isn't
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18 comments
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No it's 51
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Naw, 5 + 1 = 6, 6 is divisible by 3, so 51 is divisible by 3.
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I shared this at work recently and nobody cared. 3 6 and 9 are all kinda special.
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Only if you weren't taught (or were, but too long ago lol) the divisible by 3 rule - if the sum of the digits is divisible by 3, so is the whole number. 5+1=6 therefore 51 is divisible by 3! Bonus division rule - if it was also an even number and therefore divisible by 2, you could deduce that the whole number was divisible by 6.
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Actually 51/3! Is 8.5
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You bastard
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Actually, 51 is not divisible by 3!
It is divisible by 3
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Hilarious.
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Agreed. 51 looks prime AF.
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Surely it's 1? Looks prime, and some people will even argue that it is!
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Its only factors are 1 and itself after all
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18 comments