This Two-Variable Relationships in Real-World Problems lesson plan also includes:
When tending to CCSS.Math.Content.6.EE.9, this complete resource fits the bill. Learners work in groups or pairs to assign two variables to several real-world problems. They write equations, complete tables of solutions, and then construct graphs. Activites are provided to be printed out for your class, in addition to two related homework assignments. If your class already has an understanding of variables and equations, this would be an ideal instructional activity to follow.