20 system of equation problems with multiple choice answers. Emphasize that students must solve using substitution and show their work otherwise students could potentially work backwards.
I've heard this lesson plan format called a "scavenger hunt" or "trail run". Each problem is hung on the wall (I recommend the use of page protectors so that students don't write on the paper.) I allow my students to work in pairs and travel at their own pace. Completed correctly students will circle through all 20 problems and return to their starting point. The order is provided on the last page. I have also provided a student work sheet. It is important to emphasize that students should not use process of elimination because that can result in a heavily errored order. I tell students to visit me at my desk if they are sent back to their starting place before they have done 20 problems.
Please email me with questions. This format of lesson is great for student engagement and gets them out of their seats and moving around talking about math!