Common Core Math Standard: (4.OA.4) Using prior knowledge of factors and multiples, SWBAT identify prime and composite numbers from 1 – 100. Greek philosopher and mathematician, Eratosthenes, created a method for finding prime numbers using a hundreds chart. Learners will discover the history of Eratosthenes, as well as the step-by-step method of finding prime numbers up to 100. A recording sheet is given to reinforce and practice, finding the first 25 prime numbers. For extension, an optio