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
Sets A-F are the same worksheet with different questions - print any (or all) for fresh practice.
Grade 5 Prime & Composite
Sets A-F are the same worksheet with different questions - print any (or all) for fresh practice.
Grade 6 Prime & Composite
Sets A-F are the same worksheet with different questions - print any (or all) for fresh practice.
Frequently asked questions
Are these prime & composite worksheets free?
Yes. Every worksheet on ChalkBee is free to view and print or save as a PDF, with no login required. Pro unlocks the printable answer key and removes the watermark.
Do the worksheets have answer keys?
The answers are computed in code from the exact questions on each sheet. The printable answer key is available with Pro.
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.