Answer: All the natural numbers can be expressed as 6n+0, 6n+1, 6n+2, 6n+3, 6n+4, 6n+5, n >= 0. 6n+{0,2,4} are all even and 6n+3 can be divided by 3, so they are not prime numbers (2 is prime, but the problem is asking prime >= 5, so we ignore 2 here). Therefore, prime numbers can be only in two forms: 6n+1 and 6n+5.

Let p1 = 6n+5 and p2 = 6(n+1)+1, there is only 6(n+1)+0 between them, which satisfies the constraint in problem description. Then, p1 + p2 = 6n+5 + 6(n+1)+1 = 6(2n+2) which obviously can always be divided by 6. Note that p1 and p2 can be any two natural numbers satisfy that constraint, therefore two prime numbers. This example concludes our proof.

OK, let’s get into what I want to say today.

As you know, or maybe you don’t know, there is a big bad thing going on in Tibet. Many people in the rest of the world don’t know the truth of Tibet problem in China, because some “anti-China” media like to mislead people, I guess. So, if you want to hear some voice from inside of the country, please watch the video:

(Caution: The words in this video clip are defensive and against some other countries.)

via GOOD Magazine