Recognise prime numbers
- Test divisibility by small primes.
- List any factor pairs.
- Prime numbers have exactly two factors.
Answer: 17 is prime because only 1 and 17 divide it
🔢 Number
Prime numbers
Learn prime numbers with a GCSE-style explanation, help guide, worked example, practice question and flashcards.
Global XP
Level 10 / 100 XP
1. Explanation
Key idea
- Prime numbers is part of number and appears often in KS3–GCSE maths.
- Prime numbers have exactly two factors: 1 and themselves.
- Use the worked model, help guide, interactive question and flashcards to practise prime numbers until the steps feel automatic.
Real-life examples
- Shopping, sport, travel, science, design and everyday decisions all use this skill.
2. Visual
Prime numbers learning map
Understand the key idea → follow the help guide → practise a question → check your method → build speed with flashcards.
3. Help guide
How to tackle Prime numbers
- Learn the rule: Prime numbers have exactly two factors: 1 and themselves.
- Worked model: Test divisibility by small primes. List any factor pairs. Prime numbers have exactly two factors.
- Try the interactive question without looking at the answer first.
- Use the flashcards to test the rule, the method and a common check.
4. Worked examples
Step-by-step working
5. Interactive questions
Try it yourself
Is 29 prime?
6. Flashcards
Master quick recall
Flip each card, then choose whether you know it or need more practice.
0 mastered
FrontRule for Prime numbers
BackPrime numbers have exactly two factors: 1 and themselves.
FrontExample answer: Is 29 prime?
Back29 has no whole-number factors except 1 and 29, so it is prime.
FrontCommon check for Prime numbers
BackCheck units/notation, compare with an estimate, and make sure the answer matches the question.
7. Finish
Complete this topic
When you have read the examples, tried the question and reviewed flashcards, claim your topic completion XP.