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.

This prime factorization worksheet lets 5th graders complete five factor trees and write each number's prime factorization. A full answer key is included, making it perfect for no-prep practice, homework, or math centers.

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.