Penny Puzzles are a great way to introduce the concepts of variables and solving equations. Students use logic and reasoning to determine the number of pennies hidden in paper bags. Then, students use variables and expressions to model/represent the puzzle. Through cancellation and equation balancing, students learn to solve two-step equations. This activity gives students a real-world example of algebraic reasoning and allows them the opportunity to take an active role in the learning process.
Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities.