Saturday 16 June 2012

A Grouping Activity

In today's blog post, I'm going to be sharing with you one of the first classroom activities I was ever taught. As a would-be teacher I mean, not as a student.

It was the second day of my PGCE, the first day that we were separated into subject groups, although a lot of us maths lot managed to find each other on the first day anyway. I suppose geeks, like insects, give off pheromones that signal to others of the same species.

We were each given a number. For the sake of simplicity, let's say we were given the numbers 1 to 36. As memory serves, there were actually over forty of us. But let's not let accuracy get in the way of a good story.

On each of the six tables there was a piece of paper saying one of the following:
Prime numbers
Square numbers
Triangle numbers
Numbers greater than 20
Even Numbers
Numbers with more than four factors.

We had to join a group corresponding to our number. As I recall my number was 3. I could have joined either the prime group or the triangle group. Some numbers could have belonged to three different groups. The number 5, for example, had no choice in the matter. The catch was this: every group had to have exactly six members.

I could tell you the solution to this problem, but I'll leave that for you to work out. Feel free to email me ( if you get stuck. The one hint I will give you is that a girl named Lydia worked out pretty quickly that because both of our numbers were triangular but not square, we would have to be in the triangle group. And that is the story of how how me and Lydia became friends* and how Team Hopper (previously known as Team Triangle Numbers) was formed.

*OK not really, but I repeat: let's not let accuracy get in the way of a good story.

I think this activity would be a cool way of getting a class of pupils into groups. It's pretty challenging, so maybe best saved for A level classes? Obviously it will need adapting, as if you have 36 students in your A level maths class, you are clearly working at the wrong school.

Emma x x x

PS My blogiversary is coming up, so expect some interesting posts in the near future.


  1. And as a result of this being successful with our group, i attempted it with my year 10s. Worked pretty well with this age group. Batesy x