Prime Numbers

0 and 1.

A number is either a prime number or a composite number except for...

is divisible by 5.

Any number greater than 5 that ends in a 5...

No

Are 0 and 1 considered prime numbers?

Any number, greater than 1, that is not prime.

Composite number

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97

First 25 prime numbers

First try dividing it by 2, and see if you get a whole number. If you do, it can't be a prime number. If you don't get a whole number, next try dividing it by prime numbers: 3, 5, 7, 11 and so on, always dividing by a prime number.

How to prove if a number is prime.

that number is divisible by 3.

If the sum of a number's digits is a multiple of 3...

ends in a 5.

No prime number greater than 5...

A number divisible only by 1 and itself.

Prime number

2

The only even prime number.