Contributed by
Kelly Vaughan, November 13, 2013

**CCSS.Math.Content.8.F.A.1: Understand that a function is a rule that assigns to each input exactly one output.**

Students create function machine programs and challenge each other to figure out the function from the inputs and outputs. Basics of Scratch, includes simple lists.

Third in a series of lessons introducing programming and aligning to Common Core Standards. The idea is that it may help more teachers participate in Hour of Code in December. In this lesson, the function concept is reviewed and students create simple programs that work as function machines. Then they switch programs and try to figure out the function from testing inputs and outputs.