Mathematics?

Question

Do you know the easiest method to prove the numbers as prime numbers??

Answer 1

There is no easy way to proove a number is a prime number - the only thing you can do is divide it by all the smaller primes (up to the square root of the number) and see if it is prime or not.

The way to proove there are infinately many primes is:
Assume there are finitely many primes
Then let N1, N2, N2... Nz be the primes
Multiply them all together and add one.
Now this new number is not divisible by N1or N2 ... or Nz as it would always leave a remainder 1, so the new number is also a prime not in our original list. Which is a contradiction. So there must be infintely many primes.

Answer 2

If you mean - is there an easy way to tell whether a particular number is prime - then the answer is no. You have to show that it cannot be divided exactly by all the primes up to the square root of it. (There are easy ways to show that any large number can be divided by 2 or 3 or 5 but not for primes from 7 upwards - anyway none that I know of.)

Incidentally the fact that it is difficult to decide whether a very large number is prime or not is the basis of modern encryption technology.

Answer 3

Here are some methods.
1. Number ending in 2,4,6 or 8 is not prime.
2. If a number's digits add up to a number which is divisible by 3, it is divisible by 3 and therefore composite.
(246- 2+4+6=12 12/3=4 therefore it is composite)
3. remember that if the square root results in an integer it is automatically composite

http://www.lessonplanspage.com/MathPrimeVsCompositeNumbers7HS.htm

Answer 4

How about a web script?

http://www.mste.uiuc.edu/html.f/resource/prime.html

This resource will determine if a number is prime and the calculation is accurate up through a number 16 digits long. Can it get easier?

Answer 5

Yeah . . . write a computer program to do it by brute force. That's the easiest way. Good night!