One of my favorite math activities to do with students is called, “Which One Doesn’t Belong?” This was an idea that seems to have originated with @MaryBourassa, who created a website for this. I described the concept and offered some links in this post from 2016. Recently, I saw a Tweet from @Simon_Gregg offering an entire album of over 200 WODB images for educators to use for stimulating math discussions.
Each picture set has 4 different images. Project the images to your students, and ask them which one doesn’t belong – and why? Hopefully, you will receive many different answers, and they will all be right for various reasons. Because these are so open-ended, they can be used with different levels of complexity from number sense to geometric reasoning. Encourage students to use mathematical vocabulary as they defend their choices, perhaps even making it a game where points are awarded for including particular words. Challenge the students to try to find a reason for each one of the four to be excluded from the group, not just the first one they notice. The “See, Think, Wonder” Thinking Routine would go very well with this activity. (For more on Project Zero Thinking Routines, see this post.) A formative or summative assessment option would be to ask students to create their own WODB challenges.
WODB is one of the 15 Math Sites That Won’t Make You Fall Asleep that I’ve listed on this post. I highly recommend checking out those links if you feel like you want to add a bit more zip to your math lessons – or just enjoy doing unusual math puzzles. (I’m addicted to the SolveMe Mobiles!)