I came upon a resource from Don Steward's blog, MEDIAN, found here. It was a simple worksheet which created deeper thinking from my Year 11 class. On a recent past paper all of them failed to score any marks on a straightforward simultaneous equation question. Having only taken over this class at the beginning of this year I knew they would have seen this before they just needed to go over certain strategies.
The puzzles got progressively harder but after each one a student modeled their answer to the rest of the class. This led to some great discussions on methods used as students had done it in different ways. This also prompted students to record their methods so they could then show the rest of the class what they had done. The final puzzle was the hardest and the class struggled to show this visually using the rectangles. This is where I used 'w' as width and 'h' for height and we solved it using an algebraic method.
The penny had dropped... the students then went back. annotated their drawings and were able to set up simultaneous equations and solved them to show that their diagrams and sketches were in fact true.
I followed this lesson up with some past exam style questions, lets see how they do when they are faced with similar questions on their next paper!