
5 Simple Math Problems No One Can Solve - merraksh
http://www.popularmechanics.com/science/g2816/5-simple-math-problems/
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iamcreasy
How about the prime number problem. It's simple enough to understand.

"A prime number (or a prime) is a natural number greater than 1 that has no
positive divisors other than 1 and itself. There are infinitely many primes,
as demonstrated by Euclid around 300 BC. There is no known simple formula that
separates prime numbers from composite numbers."

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williamstein
Where are you quoting this from? It's ill-defined / ambiguous as you're
stating it. I'm a professional number theorist and I don't understand what
your question is actually asking. Thanks!

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iamcreasy
I quoted it from Wikipedia. The problem is the last line. There is no known
simple formula to identify prime numbers.

Could you provide more clarification on what's wrong?

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williamstein
What is a "simple formula"? I have no idea what "simple formula" means. In
math reseacrch everything must be 100% precise and well defined.

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tf2manu994
I think they mean something a great deal faster than just dividing by each
number to check.

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SAI_Peregrinus
AKS is a primality check in polynomial time, IE much faster than trial
division. It's not "simple" for certain values of simple, but it's only 5
major steps.

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Avernar
Solved the sofa problem getting a large couch into my basement about half a
year ago. Still haven't got around to fixing the drywall...

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proto-n
discussion on reddit.com/r/math if you are interested, highlighting various
errors in the article:
[https://www.reddit.com/r/math/comments/57jfv7/5_simple_math_...](https://www.reddit.com/r/math/comments/57jfv7/5_simple_math_problems_no_one_can_solve_easy_to/)

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Ericson2314
Put these on the wall in every classroom. (And make the kids move desks into
the hall /s.)

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yayks
The goal is to find a box where A² + B² + C² = G², and where all four numbers
are integers: 3² + 4² + 12² = 13², except it is not the only goal.

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botw
"Mathematicians have tried many different possibilities and have yet to find a
single one that works. But they also haven't been able to prove that such a
box doesn't exist, so the hunt is on for a perfect cuboid." apparently,
something wrong here.

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athesyn
Simple to understand. I'm surprised clickbait like this has climbed so high up
on HN.

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ralusek
I don't really know how to prove something, but for the first problem, it
seems like any odd number multiplied by any other odd number (in the example,
they choose 3) will always be odd. This can/has been proven. Then, any odd
number, negative or positive, with 1 added or subtracted to it, becomes even.
Finally, any even number divided by two is still even and approaches two.

"Mathematicians have tried millions of numbers and they've never found a
single one that didn't end up at 1 eventually. The thing is, they've never
been able to prove that there isn't a special number out there that never
leads to 1."

Why are they trying millions of numbers? It seems like those 3 statements are
very easy to prove, and explain this "phenomenon." Also, isn't the multiplying
by 3 part kind of arbitrary. It seems like the only important part to consider
is that if the number is odd, add 1. The multiplying by 3 is unnecessary, and
could just as easily be swapped for multiplying by any odd number.

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gnarbarian
>Finally, any even number divided by two is still even and approaches two.

6/2 = 3

In fact. Every odd number multiplied by two is even.

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ralusek
Whoops, didn't think about that one very hard...

