The Sieve of Eratosthenes

Eratosthenes was an ancient Greek math mathematician that created a method to easily find prime numbers.

In this project you will find all of the prime numbers up to 200. You will use the same method that Eratosthenes devised.

This project will be completed in class on Wednesday, November 13, 2010. Please make sure to read all directions carefully to ensure that you get the best grade possible. It will be completed in class; you have three days to complete it.

Expectations for this project: Use an Excel spreadsheet to create the Sieve of Eratosthenes, Ms. Smith will

show you in class how to do the first part from 1- 100. You will be expected to create your own for 101 – 200.

Color code your sieve to show how the composite numbers are crossed out (ex: use blue to cross out all of the numbers that are crossed out by 2, use red for all the numbers crossed out by 3).

Copy your spreadsheet into a word document, and answer the following questions using your sieve in complete sentences.

o List all of the prime numbers from 1 -200.o Make a list of the first 10 numbers that are crossed out and write out

their prime factorizations.o Twin primes are two primes that differ by 2 (example 3 and 5.) List

all of the twin primes from 1 -200.o If the digits of a prime number are reversed, then the number obtained is

sometimes a prime (ex: 17 and 71). Use your list to find all of the numbers like these.

o Research on the Internet to find the largest prime number known today. Your answer may use exponents. Cite your source.

Make sure to view the rubric below for specific instructions for this project. You will be graded using the rubric.