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Prime and Composite Numbers Worksheets

4.OA
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Aligned To Common Core Standard:

Grade 4 - 4.OA

What Are Prime and Composite Numbers? Prime numbers are those values with only two factors, the number itself and 1. That means these values don't appear in other times tables other their own and of one. For instance, 11 is a prime number. 11 is divisible only by itself and by 1 only. Even if we try to divide 11 by other integers, we will not get any whole number, rather a fraction or decimal value. Some properties that primes exhibit are: Every number greater than 1 is divisible by at least one prime. Every even positive integer greater than 2 is expressed as the sum of two prime numbers. 2 is the only even prime. This means that all the prime numbers except for 2 are odd. Composite Numbers - The integers we get after multiplying the two smallest positive integers and has at least one divisor other than the number itself, and number 1 is called as composite numbers. Composite numbers are neither prime numbers nor units. In other words, numbers that are not classified as prime numbers and has two factors are known as composite numbers. All the odd integers which are not classified as prime numbers are known as composite. For example, 9, 15 25, 21, 31, etc. All the even integers which are not classified as even prime numbers are known as even composite numbers. For example, 4, 6, 8, 10, 12 etc. These worksheets and lessons help students learn how to classify an integer as composite or prime.

Printable Worksheets And Lessons




Practice Sheets - Students love to practice with the mazes so we stepped it up.

  • Composite Rocket Maze - Help the space ship find the planet by following the path of composite numbers. The beginning of the path has been done for you to get you started.
  • Green / Orange Maze Away - Give it a shot and see what you think.
  • Sammy Squirrel - Help the squirrel find his snack by following the path of composites.

Homework Worksheets - This series is built to be fun and educational for students.


Printable Quizzes - Time to see how you captured the concepts.



Why Is Everyone So Fascinated with Prime Numbers Anyway?

You with often learn about concept of primes and wondering what the big deal is with this classification. As the values you are working with increase, the frequency of primes is greatly decreased. Scientists as whole tend to believe that some where in the universe lives another form of highly intelligent beings that are, by our current understanding, too far away from us to travel and meet in person. A universally accepted theory is that the most reliable way in which we will be able to communicate with these beings is through the use of math via radio waves. Primes would be the foundation of the message that we would receive or transmit with extraterrestrial intelligent life forms. It is highly improbable that we would use an Earthly language, math on the other hand is a universal language that we can communicate in regardless of culture. Using primes would indicate a patterned form of communication that has a purpose. We use primes to encrypt communications to keep them secure as they pass across a network. When a message travels in encrypted form, it appears as nonsense, but when run through a decryption key, the transmission can be reformed into the intended original form. When you use an ATM to get money, this is how the information is kept secure. The same happens when you use your credit card on the Internet and any other form of secure information on the Internet. We will continue to find uses for primes as our intellect and technology improves.