Prime & Composite worksheets
Prime & Composite worksheets give students in Grade 4 to Grade 6 focused practice in prime and composite numbers. This page has 18 free printable sets, grouped by grade, and every set includes a computed answer key that is never wrong. Print them or save as a PDF, no login needed, or generate a fresh one.
What is prime & composite?
A prime number has exactly two factors (1 and itself); a composite number has more than two.
How to teach it
Test whether a number has exactly two factors (prime) or more (composite) using arrays. Learn that 1 is neither.
Worked example
Common mistake
Calling 1 prime, and assuming all odd numbers are prime (9, 15).
What's inside
- Is 40 prime or composite?
- Is 52 prime or composite?
- Is 41 prime or composite?
- Is 39 prime or composite?
- Is 13 prime or composite?
- Is 20 prime or composite?
Sample questions. Each set (A, B, C…) has fresh numbers and a computed answer key.
Grade 4 Prime & Composite
All Grade 4 worksheets →Grade 5 Prime & Composite
All Grade 5 worksheets →Grade 6 Prime & Composite
All Grade 6 worksheets →Frequently asked questions
Are these prime & composite worksheets free?
Yes. Every worksheet on ChalkBee is free to view, print and download as a PDF. There is no paywall and you do not need to log in or create an account.
Do the worksheets have answer keys?
Yes. Every set comes with a full answer key. For maths, the answers are computed in code from the exact numbers printed on the sheet, so the key is never wrong.
What grades do prime & composite worksheets cover?
Prime & Composite worksheets on this page cover Grade 4 to Grade 6. There are 18 printable sets in total, grouped by grade so you can pick the right level.
How do I print or download them?
Open any set, then use your browser's print option to print it or to save it as a PDF. The pages are laid out to print cleanly on standard letter or A4 paper.