The purpose of this activity is for students to plan how they might spend their own money at a fair. Students first consider what amount of money makes sense to bring to a fair. They then look at price charts and record how they would spend their money. They can decide whether they want to spend all of their money, or just some of it. Students calculate how much they are spending and how much money they have left, as they make sure they have enough money for everything they plan to buy. In the Lesson Synthesis, students discuss what influenced their decisions about spending their money. When students consider assumptions about information not given in a situation and model a situation, using a representation such as a drawing or equation, they model with mathematics (MP4).