1. Prime Numbers

2. What are they?
The ancient Greek mathematicians called prime numbers the basic building blocks of all numbers.

3. What are they?
The ancient Greek mathematicians called prime numbers the basic building blocks of all numbers. Prime numbers have exactly two factors, 1 and the number itself.

4. What are they?
1 is not a prime as it only has one factor, and primes are required to have two! 2 is the first prime number and also the only even prime number. Non-prime numbers (other than 1) are called composite numbers.

5. The Prime Numbers up to 100
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