How do we test if a relatively large number is prime?
Suppose n is a whole number, and we want to test it to see if it is prime. First, we take the square root (or the 1/2 power) of n; then we round this number up to the next highest whole number. Call the result m. Next we make a list of all the prime, whole numbers that are less than m. We must divide n by every prime, whole number in our list. If one of the prime, whole numbers in our list evenly divides into n, then n is composite. If none of the prime, whole numbers in our list divides into n, then n is prime. This is known as the prime number test. A computer chart to find prime numbers less than 200: Sieve of Eratosthenes Go to the web site above and find the primes less than 200. How do we test if a very large number is prime? Well, we can have the computer do that for us: CLICK HERE.
