University of Edinburgh

BSL Maths Glossary - prime number - Example

Subject level: General


A prime number is any number that can only be divided by itself and one. So its only factors are itself and one.
If we take the number 2. We can have 2/2 and 2/1 ( dividing by itself and by 1). So 2 is a prime number.
If we now take the number 23. Try to think what could be factors of 23. It can only be divided by itself (23/23) or by 1 (23/1).
All these numbers are odd numbers with the exception of 2 which is an even number.