Which One Doesn’t Belong?
Today I am going to share one of my favorite free websites/resources.
WODB.CA
Remember Sesame Street and the song; One of these things is not like the other, one of these doesn’t belong?
WODB.CA is full of these types of activities.
Except there is a catch!
Not just one thing doesn’t belong.
You can justify a number of reasons why each one doesn’t belong.
Let’s look at an example.
Which one doesn’t belong and why?
Take a minute to formulate your response (perhaps even more than one) before moving on.
Some possible responses:
9 - because it is a single-digit number, the others are all double-digit.
25 - because it is the only multiple of 5.
16 - because it is the only even number, the others are odd.
43 - because it is not a perfect square, 9, 25, and 16 are.
9 - because the sum of the digits does not equal 7 like the others (1+6 = 7 / 2+5 = 7 / 4+3 = 7)
I’m sure there are more - these are just the ones that come to me at the moment.
The variety and creativity of responses I generate from my middle school students always astounds me!
Whenever possible, ask for clarification.
For example when a student says “43 doesn’t belong because it is not a perfect square. 9, 25, and 16 are perfect squares.”
I might ask;
“What do you mean by a perfect square?”
“What are some numbers, based on this rule that would belong?”
“What numbers would not belong?”
The website is divided up into 3 sections. Shapes / Numbers / Graphs & Equations.
There is something for everyone!
Creating your own WODB scenario based on the topic or lessons you are currently teaching is not difficult.
Better yet - have kids create their own and share.
WOBD does not always have to be math related.
Getting students to think, articulate, and justify that thinking is powerful. These skills will serve them across all disciplines throughout their life.
Check out my Pinterest Board “Which One Doesn’t Belong?”
Follow me on Pinterest to get notified when I discover more great math education resources and ideas.
Have a look at my latest book!
Full of engaging activities for grades 4 - 12.
