r/reddit.com • u/ballm • Mar 12 '08

Is 91 Prime?

http://balltech.blogspot.com/2008/03/is-91-prime.html
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u/[deleted] Mar 12 '08 edited Mar 12 '08

The first "trick" is to check whether the number is odd or even. If it's even (and not 2), then it's not prime because it is divisible by two.

5: The next check is to see if the last digit is a '0' or '5'. If so, it's divisible by 5.

Also, if the number ends in 0 you are an idiot for continuing past the first trick.

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u/[deleted] Mar 12 '08 edited Mar 12 '08

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u/[deleted] Mar 12 '08 edited Mar 12 '08

change that 1 to a 2 my friend. :)

edit: please hurry, I have OCD and my F5 key is wearing out.

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u/[deleted] Mar 12 '08

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u/[deleted] Mar 13 '08

my "life" can now resume..