Throughout the year, we have been practicing a math routine called “Which One Doesn’t Belong?” or “WODB” for short. (Some of you tried it out at our Student Led Conferences). This idea comes from a book by the same name, written by Christopher Danielson. In the Fall, we started with sharing the book and talking about how objects might be grouped together, so that they all have something in common. Being able to describe, compare and sort objects is a part of the oral language and math components of the Kindergarten  curriculum. 

To begin, I simply write “Which one doesn’t belong?” on the white board. Next to this question is a picture with four objects or images. The tricky part – the part that gets our brains really working first thing in the morning – is that all of the objects belong to the group, but all of the objects also DON’T belong to the group. The students can choose any of the four objects as the one that doesn’t belong, but they have to be able to explain WHY. To do this, they have to use lots of mathematical thinking and dig into all that they have discovered about colour, shape, size, sorting, number, patterns and much more. This is very different (and requires much more flexible thinking) than a traditional “which one doesn’t belong” task, in which there is usually only one correct answer.

Below is the flower “WODB” we did as a class this past week. Which one would you choose? Read through the students’ thinking – they seriously knocked my socks off with their ideas! Can you think of any other reasons WHY for your choice that we could add to our list?

 

Top Left

  • because it is the only one with a smile that looks like an emoji
  • because it is the only one in a mug that you can drink out of
  • because it is the only one with a handle
  • because it is the only one that is almost all yellow

Bottom Left

  • because it it the only one that is only one colour: red
  • because it is the only one that has only one kind of flower: roses
  • because it has the most beautiful vase and red is my favourite colour

Top Right

  • because it is the only one with lots of colours
  • because it has the most flowers – too many to count!
  • because it is the only one that has a colourful background
  • because it is the only one where you can see far into the distance
  • because it is the only one where the flowers are still growing in the ground
  • because it is the only one where the flowers are in the dirt, not water
  • because it is the only one that that has a sky and clouds above the flowers
  • because it is the only one where the flowers look bigger close to us and smaller when they are far away
  • because it is the only one with tiny trees far away in the distance

Bottom Right

  • because it is the only one that looks like a pattern: pink, white, pink, white
  • because it is the only one with a clear vase so you can see the stems
  • because it is the only one with a square vase with straight sides, not curves

 

If you are looking for ways that you can incorporate more Math into your conversations with your child and would like to play with mathematical thinking at home, I would absolutely recommend checking out Christopher Danielson’s blog and signing up for his newsletter (tmwyk) at this link: Talking Math With Kids

Have fun talking math with your kids!