This Prime Numbers Worksheet helps 4th graders identify prime and composite numbers by listing every factor and explaining their reasoning in a word problem. An answer key is included, so practice is fast to assign and easy to check.

Using this 4.OA.4 Fourth Grade Common Core lesson students determine whether a given whole number in the range 1–100 is prime or composite.

Using this Planet Prime vs Planet Composite Activity, students determine whether a given whole number in the range 1 - 100 is prime or composite.