Prime and Composite Numbers to 20

Take a deep dive into prime and composite numbers to 20 with this exploratory worksheet! Geared toward fourth-grade learners, this creative worksheet is designed to help students understand how to distinguish between prime and composite numbers using multiples. Using the numbers grid provided, students will follow along with each of five steps as they identify all of the prime and composite numbers within 20.

Understanding prime and composite numbers will help students to see the relationship between factors and multiples, while also preparing them for higher level math skills, such as determining the prime factorizations of a number or determining the greatest common factor or least common multiple of numbers. 

For more fun practice with prime numbers, check out the Identifying Prime Numbers Maze next!