During a Maths learning walk last year I was in the Year 5 classroom and we were thinking about algebraic problems involving shapes, patterns and missing lengths.
I produced the sheet attached which has 2 differentiated versions of the problems.
We had spent the previous week looking at a few different variations on the same problems so this week (luckily for my observation) was one in which was just a bit of input from me but then a lot of problem solving skills from the children. They were able to use their whiteboards for any help needed but I encouraged the children to draw and write all of their thoughts in their maths books for assessment purposes. The children were all well engaged and loved the challenge posed at the end.
This would work well in Year 5 and Year 6. We were following Maths Makes Sense at the time and we found that some of the expectations were too high, so possibly even higher up would be good.
Let me know if my maths-learning-walk worksheet is any good to you! Comment below or let me know on twitter @eenalol