I'm new to this forum but I really like math and study it pretty much every day. I came across something about primes that's interesting:
Elementary prime test: If no prime is less then or equal to sqrt(m), divides m, then m is a prime.
Yes, that is true and it is interesting. It is true, of course, because if n is a composite number with factors a and b, n= ab, one of the factors must be less than or equal to sqrt(n) and the other larger or equal.