The world belongs to the mathematicians and the physicists. We lay people may pump our minds with Discovery Channel specials, but they’re the ones who get to understand how it all really works–how the ...

Three and five are prime numbers — that is, they are divisible only by one and by themselves. So are five and seven. And 11 and 13. And for each of these pairs of prime numbers, the difference is two.

A prime number is a natural number greater than 1 that has exactly two distinct factors, 1 and the number itself. So, if p is a prime number then its only factors will be 1 and p itself. 4: It can be ...