I’m about to teach upper and lower bounds after spending sometime teaching significant figures and estimation. I gave a task to my class during the lesson on SF that I realised is a good task to precede the bounds topic.

What was nice about this task that wasn’t apparent until I had given it and students (in my set 1 year 8) were trying it, was how much it encouraged students to discuss the range of possible answers. When we working through the answers, students were offering up their differing answers and then other students were commenting on whether they would round to the value required. After a few questions, students started saying ‘you can have any number between… and….’

this will make a nice opening for bounds next lesson.