Grade 5 · Year 6 · Class 5 · ages 10–11 · Number sense
Prime and composite numbers: Grade 5 practice
Deciding whether a number is prime (only two factors) or composite. Eight questions at a time, instant feedback and a mastery score from 0 to 100.
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Right answers raise your mastery score (more on harder questions) and wrong ones lower it a little. Your best score is saved on this device, and in your account if you log in.
The idea in one minute
A prime number has exactly two factors: 1 and itself. Try dividing by 2, 3, 5 and 7 to look for a factor.
Try these on paper first
One question at each level. Tap a question to see the answer.
Easy Is 26 prime or composite?
Answer: composite
Medium Is 38 prime or composite?
Answer: composite
Challenge Is 85 prime or composite?
Answer: composite
More ways to practise prime and composite numbers
- Printable prime and composite numbers worksheet with an answer key (new questions every time)
- Prime Hunter: Tap every prime, square, multiple or factor hidden in a grid of numbers.
- All Grade 5 practice · Number sense worksheets
Related skills
- Squares and cubes (Grade 5)
- Factors and multiples (Grade 4)
- Roman numerals (Grade 4)
- Estimate sums and differences (Grade 4)
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Play a game that builds the same skills
FAQ
Prime and composite numbers: questions
What grade is prime and composite numbers?
It is usually taught in Grade 5 (Year 6 in England, Class 5 in India, ages 10–11), though schools and countries differ. Try the grade above or below if it feels too hard or too easy.
What does a prime and composite numbers question look like?
For example: "Is 38 prime or composite?" The answer is composite. A prime number has exactly two factors: 1 and itself. Try dividing by 2, 3, 5 and 7 to look for a factor.
What should I learn before and after prime and composite numbers?
Before it, try squares and cubes (Grade 5). After it, move on to highest common factor and lowest common multiple (Grade 6).
How can I get better at prime and composite numbers?
A prime number has exactly two factors: 1 and itself. Try dividing by 2, 3, 5 and 7 to look for a factor. Practise a little every day, read the hint after each wrong answer, and use the printable worksheet when you want to write it out.
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