One of my go-to places for ideas for our units is the NSA website! Yes, the National Security Agency sponsors math workshops where teachers write some awesome units! Check out this website ... note the grade level links on the right side.
I took one of the units on developing the concept of slope as rate of change apart. From the unit I pulled out 5 excellent examples for students to work on in class using "I do, We do, You do" model. I can do one problem for students, then they can do one in their team. And last there are 3 problems for them to work on independently.
Knowing that interpreting problem situations is challenging for my students, I found, borrowed, modified nine other problem situations found online to create a poster project that students will do in teams. Each team will illustrate one problem, graphing it, and analyzing the x and y intercepts. Each team will present their problem. Then all students will complete all nine problems for homework.
In our curriculum this work comes before actually teaching the various equations of lines and formulas. So the work is more conceptual, more about giving meaning to slope before applying it to "naked" abstract linear functions.
During this unit I'll use Three_ways_for_finding_slope_foldable that I found on the Utah Education Network. I'll introduce the foldable after we explore the problem situations above.