A sieve is a way of getting rid of something you do not want. Then, you can keep what you want. This program will teach you how to use a special kind of sieve. This is a sieve in math, called the Sieve of Eratosthenes.
I like m & m's, but I only like the red ones. When I get a package of m & m's, I get rid of all of the other colors, except red. So, I throw out the brown, yellow, orange, and blue ones. This mean I only have the red ones left. This is kind of what the Sieve of Eratosthenes does. This sieve can help you find a special kind of number, called a prime number.
Prime numbers are numbers that can only be divided by 1 and itself. For instance, 2 is a prime number because 2 can only be divided by 1 and 2 evenly. Sometimes prime numbers can be hard to find. Rather than simply guessing at numbers and seeing if they are prime, Eratosthenes came up with a way to find prime numbers. He took a group of numbers and put them through his sieve. That way, he knew that he had found all of the prime numbers in that group of numbers.
When doing the model, try to find the pattern. Then, you will understand how the Sieve of Eratosthenes works!
In this activity, you will learn what prime and composite numbers are.
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This project is supported, in part, by the National Science Foundation
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