I've written quite a few posts recently about using ratio tables extensively in my teaching for proportional reasoning. Following the explosion on Twitter about Edexcel's non-calculator paper last Thursday, I thought it might be time for a critical evaluation on my part of just how useful (or not!) they are in tackling any or all of the proportional reasoning problems on the most recent paper, particularly if we should see this as an indicator of things to come, as @El_Timbre suggested in this brilliant blog post on Sunday. 

I'm approaching this from the point of view of pupils aiming for a grade C, as I've had borderline groups for the last two years, and no top GCSE sets for about four, due to having plenty of A Level Maths on my timetable already, so I'll admit that my pedagogy and knowledge of grade A/A* topics at GCSE is fairly limited.

Tonight's post is another quick one about using ratio tables, this time for solving proportional reasoning problems. I've previously blogged about using them for percentage calculations and converting fractions to percentages, so thought that a post on general proportional reasoning was long overdue! Note: The ideas detailed in this post took a good few lessons to work through, and we supplemented the discussions with lots of related practice. 

By the time I got to proportional reasoning in our scheme of work this year, my classes had already had quite a lot of experience in using the bar model for solving fraction problems. I started off by working through one of the superb lessons I had from the NCETM last year, which looks at proportional reasoning using a bar.

It's no secret that I'm a big fan of bar modelling to get pupils to really think about the calculations they are doing. It's a great way to introduce work with percentages too, and solidifies the link between percentage and fraction calculations. One particular advantage is the flexibility it affords - I had one pupil decide that the best way for her to find 15% was to work out 25% and 10%, then subtract one from the other, rather than the more "traditional" method we'd probably all teach of finding 10% and 5%, then adding together.