Welcome to the mysterious world of prime numbers. Prime numbers can be found across all aspects of mathematics, even in Magic Squares, which we’ll cover in upcoming posts.

What is a prime number? A prime number is any natural number, (1, 2, 3, 4 etc.) with no factors other than itself and 1.

A prime example (yes, pun intended) is the number 19. 19 is prime as 1 and 19 are its only factors as 19 x 1 = 19

The first prime number numerically is 2. 2 is a special number in the prime world, as it is the only even prime. It’s quickly followed by prime numbers: 3, 5, 7, 11, 13, 17 and so on.

On the opposite end of the spectrum you have composite numbers. A composite number is one that has factors other than itself and 1.

Take the number 24. It is a composite number because it has factors of 1, 2, 3, 4, 6, 8, 12 & 24.

So, are all natural numbers simply either prime or composite? This is a trick as there is one exception…the number 1. The natural number 1 is neither prime nor composite.

Mathematicians throughout the ages have been fascinated, (and frustrated) by both the simplicity and complexity of prime numbers. There’s simply no rhyme or reason, no science behind their order.

Now you’ve learned the basics. Read on in this series to explore the world of prime numbers.