The goal of this lesson is for students to use manipulatives to add integers, creating concepts rather than memorizing rules. This lesson will be related to the 300 Spartans who battled the invading Persians at the Battle of Thermopylae, inspiring the hit movie "300" and Stephen Pressfield's historical fiction, The Gates of Fire. Interdisciplinary connections will be made to literature, theater, and history, discussing why Pressfield called this the most important battle in establishing and securing democracy in western civilization. This lesson is a base for many subsequent lessons including subtracting integers, combining like terms when simplifying algebraic expressions, and solving algebraic equations.This lesson plan was created as a result of the Girls Engaged in Math and Science, GEMS Project funded by the Malone Family Foundation.