Prime Suspects

Contributor: Danielle Childers. Lesson ID: 10960

Can you give a prime example of a composite number? Prime and composite numbers are different! You will learn why and choose your own cool presentation!



learning style
Auditory, Visual
personality style
Golden Retriever
Grade Level
Intermediate (3-5)
Lesson Type
Skill Sharpener

Lesson Plan - Get It!


There are four numbers in a police line up: 4, 13, 28, and 117. One of these numbers is a prime suspect because it is a PRIME NUMBER! How dare a number be prime, refusing to be divided any smaller number — how horrible!

  • Do you know which of the numbers above - 4, 13, 28, or 117 - is prime?

For a good review, watch Prime Numbers and Composite Numbers (below):

After watching the video, explain out loud what it means for a number to be prime in your own words and give an example of a prime number.

The man in the video showed you how to find out if a number is prime or composite by finding the number's factors. On the Pre-Algebra Help Lesson: Prime and Composite Numbers from, they show you another way to find out if a number is prime or composite.

  • After reading through the site, which method helped you better understand how to find a prime and composite number?

Before moving on, check out one more explanation about Prime Numbers and Composite Numbers on the Math Is Fun website. It extends the information you learned in the video to help you better visually understand the concept.

When you're ready, visit the Got It? section to practice what you know about prime and composite numbers!

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