5 Simple Math Problems No One Can Solve

by merraksh • 10 years ago

52 23 10 years ago

popularmechanics.com

Ericson2314• 10 years ago

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

athesyn• 10 years ago

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

iamcreasy4• 10 years ago

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."

williamstein2• 10 years ago

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!

hilop• 10 years ago

https://en.wikipedia.org/wiki/Prime_number please improve the article :-)

iamcreasy4• 10 years ago

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?

cyphar2• 10 years ago

Finding primes is a P problem though, so I'd consider it a "solved problem". There's no equation that generates nothing but primes, is that what you meant?

iamcreasy4• 10 years ago

Yes, kind of.

YomiK• 10 years ago

There are many such formulas, such as Willan's 1964 simple formula for the nth prime. But they are basically all hiding a sieve, Wilson's theorem, the prime count function, or some other calculation. That is, none of them are at all practical, and most offer no insight.

I'd recommend perusing "Formulas for Primes" by Underwood Dudley, 1983. Free online link: http://www.maa.org/programs/faculty-and-departments/classroo...

ralusek2• 10 years ago

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.

25cf• 10 years ago

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

This isn't true.

gnarbarian• 10 years ago

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.

ralusek2• 10 years ago

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

StefanKarpinski• 10 years ago

If you're still within the edit timer, you should really replace this comment with "I have discovered a truly marvelous proof of this, which this margin is too narrow to contain." Maybe they'll rename the conjecture after you.

yayks• 10 years ago

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.

botw• 10 years ago

"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.

Avernar• 10 years ago

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...

proto-n• 10 years ago

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_...

5 Simple Math Problems No One Can Solve

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