Represent unknown quantities and mathematical relationships using variables

Big Ideas: Any algebraic expression can represent a range of numbers, a single number or a group of varying numbers. Variables are tools for expressing mathematical ideas clearly and concisely. Variables can have many different meanings, depending on context and purpose. Students will represent the cost of a concession purchase with variables for the number of items purchased. Students will understand that variables represent single numbers that can vary. Students will chose their variables and understand that the definition of the variable depends on the problem context. Students will also write equivalent expressions, although this is not the focus of the task. This task should come near the beginning of a unit on Expressions and Equations or before discussing independent and dependent variables. Vocabulary: variable, expression