1. Maths Rich Task 1: Positive Differences
mr barton maths .com

2. Rich Tasks and Probing Questions
I believe it is far more important to plan prompts and questions than worksheets and PowerPoints. Prompts and questions give you much more scope for flexible, fun lessons and allow for effective differentiation. They allow you to start everyone off on the same task, and then wander around the classroom, seeing where the students are up to, dropping little prompt cards on different students’ desks with a new line of inquiry for them to investigate. They also allow students to express themselves creatively, coming up with their own lines of inquiry to investigate.
Have a play around with the following task, and then please share your ideas for extensions, simplifications, modifications, probing questions and lines of inquiry in the comment box at the bottom of the TES resources page.
For the full collection of these activities, and more about the pedagogy behind them, please click here

3. Background on the Task
This is a task I first saw on Den Steward’s absolutely amazing Median Maths Blog. The link to the original task is here
I have since used it with classes ranging from a bottom-set Year 7 to my top-set Year 11s
No equipment is needed, just a few copies of the blank grids for students to experiment with
I have included an Excel spreadsheet I created which can be used to check students’ answers or extend the task

4. Positive Differences: Instructions
Choose any 3 numbers to fill the bottom row of circles
The next row is generated by working out the positive difference of each pair of numbers

5. What questions would a mathematician ask?
Please share your ideas for extensions, simplifications, modifications, probing questions and lines of inquiry in the comment box at the bottom of the TES resources page.