Eratosthenes, a brilliant mathematician in history, devised the sieve analogy that he used to separate prime numbers from composite numbers. The importance of prime numbers is discussed as being the foundation all of natural numbers. Some interesting background on prime numbers is provided for students, and there are actually two activities contained in this product, a follow-up pictorial biographical research assignment (with rubric) is included, and you will be able to display this work in your classroom. Additionally, there is an option at the end of the two activities for your students to answer an extra-credit research "challenge" question. You may wish to separate the two activities and do them on two separate days. Kids always seem to love finding the prime numbers using Eratosthenes' method!