• Alex Box

Connecting maths and people through WODB

Updated: Jun 5

Which one doesn't belong? The top left, top right, bottom left or bottom right? And what's your argument for why?

Which one doesn't belong? - a prompt from Simon Gregg

Which One Doesn't Belong? (WODB) is a fun and inclusive #MathsTalk routine. With plenty to observe, WODB? prompts are accessible to all and so a great routine for the whole class. I particularly love how it builds respect and connection within the class - for now, I'm putting this down to the diversity of ideas and observations that come out in the discussions. It's a rich and collaborative experience where learners become genuinely interested in the ideas of others, and that sharing of ideas leads to learning.


Example thinking of one person (me)

Looking at the fruity image above, and posing an argument for 'which one doesn't belong?' here, I'll personally have an initial urge to count. I'll subetise 1, 4 and 5; all collections but the top right (TR) which is 'unsubetisable' - my first reason for the why the TR doesn't belong.


The thinking continues

While that first argument seems somewhat satisfying, there's visually lots happening here - lots to notice and think about. I'm looking for the oddness or evenness of each collection. No obvious leads there. But now I'm and thinking about each of the four numbers - 1, 4, 5 and 10. The 10 limes are the only triangular number! Oh, hang on... 1 is a triangular number too. And now I'm thinking about triangular numbers.... back to the task at hand.

I'm also drawn to the neatness of the lime triangle and am thinking about it in terms of symmetrical lines - I can count three.


With fruity details like plant stalk markings aside, I start counting lines of symmetry and am a bit stuck at the melon...(or what Simon later informs me is a pomelo - the learning continues ;)). Are there.... infinity lines here? This is where I'd love to have people around me to talk it out with!



Sourcing WODB? prompts

There are bucket-loads of prompts online. My two go-to places are this website by Mary Bourassa and this gallery of prompts by Simon Gregg where the above, fruity prompt comes from.

Designing WODB? prompts

I've also started designing WODB? prompts that 'nudge' toward a particular idea. For instance, I might want to create multiple opportunities for students to think about or make sense of five frames or ten frames and their purpose. WODB? is one great context for that.


What I've enjoyed about designing WODB? prompts is bringing in multiple, connected ideas - making sure there's plenty to notice and think about, and ensuring there is at least one reason why each quadrant might not belong.

You can access these files in this google drive folder.


Use in class The breadth and depth of responses that come out when there's a whole class involved, hasn't failed to surprise and energise me yet.


It's a great investment of time. In as little as 5 to 10 minutes, the group engages in a range of thinking - comparing and contrasting, constructing arguments, communicating reasoning and considering other perspectives. And all this, in a way where they touch on and connects various mathematical ideas. And each other.


What's your experience using WODB? in the classroom? I'd love to hear :)

If you’re looking for more ways to engaging all students in maths,

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