This task draws upon a task in the Standards Units which I am very fond of. I have written this for two reasons. 1. To reduce the complexity so that it can work in the introductory block with new S1 in August. 2. Because collaborative tasks and card sorts are unlikely to be feasible pedagogical choices in the short term.
Question 2 is one I am quite proud of, as this draws out one of the key ideas of the original task: that different expressions represent the same area.
Credit: @chrismcgrane84, inspired by Standards Unit Task