Rationale: This activity provides practice finding the value of an 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:
- 3rd – 5th as long as modeling has taken place and any self-selected strategy is accepted
- 7th – 8th for students who are struggling with the concept of balancing equations.