Which One Doesn't Belong? is a book of conversation starters around geometry. Each page of the picture book gives readers 4 shapes and asks the questions, "Which One Doesn't Belong?" I know this opener and love it and have used lots of the resources on the website Which One Doesn't Belong? and other resources and I've always found the routine to be a good one for math learning and supporting conversations around math.
But there was so much I didn't know! This teacher guide--which is not so long but long enough to have depth and lots of new learning--helped me to understand how much more powerful this routine could be if I were more intentional as a teacher. The focus on geometry is interesting to me because it is an area of math teaching that I need to learn more about. The book has an entire chapter called "How Children Become Geometers". This chapter helped me see the big jump kids do from elementary school to high school geometry and how much better we can do to help them build understanding by understanding the levels of understanding kids have and build around geometry.
The book is not a teacher's manual. Instead it is a way for teachers to use this routine in ways that empower students. Christopher Danielson shares language he uses when he introduces Which One Doesn't Belong. He shares examples from classrooms and he helps us better understand how children make sense of geometry through inquiry. He also puts the teacher in the decision-making chair as he invites us to make our own decisions about which pages to introduce to children when. He also has tips for creating your own WODB set.
I love the answer key in this book. The thing about this WODB sets is that they are designed so every answer could be the correct answer. So the answer key shares insights kids may notice about each shape and how they might respond. It is a great resource and a great place to understand how to create your own sets (and help kids create their own.)
I love so much about this set of books. We had a conversation around the first page of the picture book last week and it was incredible. I introduced it as Danielson suggests in the book and we could have gone on for a very long time with ideas and thinking around these 4 shapes. I am excited to see where the conversation goes over the next several months. This was a great way for me to take a routine I know and really deepen my understanding of it which will help my students. Not only that but it helped me understand geometry in general and I now see the connection between this and several of Danielson's blog posts. I can't recommend this book enough. If you are interested in inquiry based thinking and routines that empower kids AND if you want to learn more about quality talk in the math classroom, you need this book immediately!