Year 8: Prime numbers

Prime numbers are whole numbers that are only divisible by 1 and themselves. Let's break it down!

What is a Prime Number?

A prime number is a whole number greater than 1 that has only two divisors: 1 and itself. For example, 7 is a prime number because you can only divide it by 1 and 7.

Examples of Prime Numbers

• 2
• 3
• 5
• 7
• 11
• 13
• 17
• 19
• 23

What's NOT a Prime Number?

Numbers that are NOT prime are called composite numbers. These numbers have more than two factors. For example, 6 is not a prime number because it can be divided by 1, 2, 3, and 6.

How to Check if a Number is Prime

1. Start from 2 and go up to the square root of the number.
2. If the number is divisible by any number in this range, it’s not prime.
3. If no number divides evenly, it's a prime number!

Important Note

1 is NOT considered a prime number. Prime numbers must be greater than 1.