### A sieve is a kitchen utensil that is used to strain solids from liquids or for separating coarser from finer particles. The **Sieve of Eratosthenes** is similar because it’s used to separate out all the prime numbers from a given set of numbers.

**Sieve of Eratosthenes**

### Spark your math thinking!

1. Set up your math mini spark recording page: #5: Sieve of Eratosthenes

2. Listen to the pronunciation of Eratosthenes several times. Practice saying “Eratosthenes”

3. Learn about Prime Numbers at Math is Fun and then answer these question on your recording page. What is a prime number anyway? What is the smallest prime number? Is 1 prime? Why or Why not? Are all odd numbers prime? How many prime numbers are there between 1 and 100?

4. Watch this video about the Sieve of Eratosthenes.

5. Do this online prime number activity and Add a picture of the finished chart to your recording page. If you would rather use paper, print out this 100 chart and find the prime numbers.

6. Read this article and find out about Eratosthenes. Consider the following questions as you read and record your responses on your recording sheet.

What were 2 of Eratosthenes’ nicknames and what did they mean?

What is Eratosthenes known for besides the Sieve named after him?

What kind of man was Eratosthenes?

7. Share your math mini spark recording page with your teacher/EY coordinator.

The two nicknames are Beta and Pentathlete. Beta means something that could be used as an insult or a compliment. Pentathlete means to be very good at 5 sports, but probably will not be a champion in the individual sports.

One is NOT a prime number, a prime number has only two factors, itself and one. It can’t be multiplied by any other numbers.

He is known for proving an accurate estimate on how big earth is along with inventing his sieve for prime numbers.

What a lot of steps! I did this.

The steps are big, but I did them and now I understand how to do them. Before I met with Mrs. Spady, I had never heard of these steps before. I knew about strainers/seives before, but I never knew they had a name in math. Thank you Mrs. Spady!

How interesting these steps are. They are a little difficult too.

This is a hard math minute to do but the more you think about it, the easier it will get.

This was fun, but hard. At the end it made more sense.

Eratosthenes was a ancient Greek mathematician that invented prime numbers.

All numbers that are even are prime

Actually, all even numbers but the number 2 are composite. Prime numbers only have 2 factors, 1 and itself. Composite numbers have more than 2 factors. All even numbers have 1 and itself as factors, as well as 2 because they are even.