Key points
A number is a number that has exactly two - itself and 1. There are an infinite number of prime numbers.
Numbers that have more than two factors are called . They can be expressed as a of prime numbers.
The number 1 is not a prime number or a composite number. It is often referred to as a unit.
The only even prime number is 2. All other even numbers can be divided by 2
Knowledge of prime numbers helps in understanding of highest common factor (HCF), lowest common multiple (LCM) and product of prime factors.
Knowledge of prime numbers is helpful in supporting understanding of (HCF), and .
Back to top
Prime numbers activity
Play this game to find all the prime numbers up to 100.
Back to top
What is a prime number?
- A prime number has exactly two – itself and 1. This means it also only has one .
- A prime number is only divisible by itself and 1
Prime numbers are used to:
- find the (HCF) and of two or more numbers.
- break down a into a product of its prime factors.
End of image gallery
Question
Which numbers between 80 and 90 are prime numbers?
80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90
Back to top
Practise prime numbers
Practise what you've learned about prime numbers with this quiz.
Quiz
Back to top
Real-world maths
Prime numbers are important in creating digital security systems (cybersecurity).
The prime numbers used to secure data through encryption are extremely large. You can multiply two very large prime numbers together, but it is difficult to break that number back down and find the factors.
This is part of what keeps information secure.
Video
Keeping online information secure is very important for businesses.
Watch the video to listen to Kim, a textile designer, discuss how prime numbers help her when selling silk scarves online to her customers.
Back to top
Game - Divided Islands
Play the Divided Islands game! gamePlay the Divided Islands game!
Using your maths skills, help to build bridges and bring light back to the islands in this free game from BBC Bitesize.
Back to top
