Linear functions provide a great introduction to function concepts of input and output as well as giving students insight into the relationship between tables, equations and graphs. This mission is aligned with Common Core State Standards: 8.FA.1, 8.FA.2, 8.FA.3, HSF.BF.A.1.A, HSA.CED.A.1, HSA.CED.A.2.
The fun stuff:
Magic genies! They take your candies and then return a different amount, sometimes more (yaay!), sometimes less (boo!). Why? How? Because they are functions and they do arithmetic!