Which One Doesn't Belong?

My class has been using a great thinking routine called Which One Doesn't Belong (check out the #WODB hashtag on Twitter for lots of examples), which asks students to practice logical thinking, and to communicate using mathematical language.

You can project the four choices and have students signal a number from 1 to 4 to show which one they think doesn't belong, and then call on a student to give reasoning. You can also ask students to move to four corners of the room, share their reasoning for choosing that option with other people in that corner, and then share out to the whole group. You can also use it as a written check / ticket out the door activity to get a measure of individual thinking.

I decided to extend this activity by taking it into our maker space this past week so students could build their own options. (So much fun, right?)

I gave them time to choose their four numbers the day before. Since we are currently studying fractions, I asked them to create fractions for their choices, which ended up making the building part a little more challenging. During this planning step, I showed them an example of a bad WODB - with options 3, 5, 7, and 10. Since 10 is a double digit, and it's composite, it's a pretty obvious standout. I encouraged students to find ways to make any one of their numbers a reasonable choice - and this is harder to do than it sounds. The next day, we went to our maker space to build their ideas.

As you can see, some students went with a minimalist approach, while others show a love for bling!

I could tell a lot about student thinking through their conversations during the building process, and from their final products - some students found unique ways to group 3 of 4 numbers in their sets, while others had pairs of differences. Some of them used the materials in very unique ways, while others gravitated toward ideas they saw around the room.

This was our first attempt - both at creating group sets and building with these materials. We still need some practice representing all the numbers clearly for others to view and consider. We still need some practice thinking about how fractions can be alike and distinct. With only 15 minutes of planning and 35 minutes of build time in our packed schedule, more time for feedback and revision would have been helpful to groups.

We had so much fun, and there was so much engagement! I would definitely recommend this as an activity to try again.