Rationale: Students need to be able to use variables to represent numbers. This activity gives them an opportunity to represent a problem as an equation with a letter standing for an unknown quantity, and to use self-selected strategies to find the value of the unknown number.
CCSS: 6.EE.B.6 Use variables to represent numbers and write expressions when solving a realworld 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.
Other grade levels this could work for:
- 3: 5 as long as modeling has taken place and any self-selected strategy is accepted
- 7: 8 for students who are struggling with the concept of balancing equations
