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In Part 1 of this blog, we introduced you to Which One Doesn’t Belong? (WODB) and discussed how to apply the SAMR Model and the Triple E Framework in your instruction with WODB. Today’s post lets us dive into the practical side—how to use this tool in your classroom to spark curiosity, deepen reasoning, and build community. You’ll receive detailed instructions and classroom ideas that support all student learners. 

The WODB visual prompt features four objects in a 2×2 grid—each with distinct attributes that invite multiple interpretations. Categories include Shapes, Numbers, Graphs, Expressions, Photos, and more, engaging students from kindergarten through high school. Instead of seeking one correct answer, this tool celebrates diverse reasoning. 

Getting Started with Which One Doesn’t Belong?:

You do not need to sign in when you arrive at the site—just begin! Scroll to find the category that you want to “play.” The seven categories are listed at the top of the website, or you can scroll down to view a preview of each topic, as shown below. Click on the topic you want to use.

Below are several examples of what you will find within each topic. Each topic includes at least ten sets of images, and the category/topic is listed with each set of images. The Miscellaneous category encompasses a diverse range of images and topics, including music, driving, and many others. 

The Photos option is ideal for all ages. Even students who are not yet reading can participate in the photo games.

Some other topics are directly related to math, as shown below.

If you want a new spin on this activity, try the Incomplete Sets. In this sequence, you do not find the one that does not belong. Instead, you are creating what would best complete the set and why. Once again, there are no wrong answers—only thoughtful reasoning.

When you find the set you wish to use, click on the small image to enlarge it. The game (2×2 grid) will open as shown. When you finish that set, click the X and return to find another one to try! 

Classroom Implementation Ideas:

Which One Doesn’t Belong? presents four objects in a 2×2 grid where any one can legitimately be the “odd one out,” creating space for multiple valid perspectives. Instead of seeking one correct answer, this tool celebrates diverse reasoning. 

Below, we share 12 ideas for using WODB in your lessons. 

1. Use in math class to celebrate diverse thinking and shift the focus from correctness to reasoning. Traditional math problems often have a single correct answer, inadvertently silencing students who think differently. This resource celebrates multiple valid solutions, creating space for various mathematical minds to shine.
2. Teachers can transition from answer validators to discussion facilitators. Use key phrases such as “Tell me more about your thinking,” “Who sees it differently?” “What do others think about that reasoning?” or “Can anyone add to that idea?”
3. Start each day with a quick 5-minute discussion using this resource. Project a set on your board and let students share their thinking as they settle in. It’s a perfect warm-up (Do Now activity)  that engages students’ minds and builds classroom community.
4. Challenge students to create their own “Which One Doesn’t Belong?” sets based on current learning topics. They can photograph objects, draw shapes, or arrange numbers. Then have classmates discuss each other’s creations.
5. Provide different sets to various groups based on their readiness levels. Advanced learners might work with complex algebraic expressions, while others focus on basic geometric shapes using the same routine structure.
6. Incorporate this routine into science (classifying animals, rocks, or plants), social studies (comparing historical artifacts), or art (analyzing artistic techniques) while maintaining the thinking structure.
7. Students with special needs may feel more confident using this site, as there are multiple entry points to ensure that every student has a voice and can contribute meaningfully to the conversation. There is not one “correct” response. 
8. Have students create digital presentations using tools like Google Slides (reviewed here) or ScreenPal (reviewed here). They can record video explanations of their reasoning and respond to classmates’ perspectives asynchronously. 
9. When introducing this routine, consider using a digital tool such as Padlet (reviewed here) to allow students to share their thoughts anonymously as they gain an understanding of the process. 
10. Use WODB to develop argumentation skills. Students must support their position with evidence and reasoning, then respectfully consider alternative viewpoints.
11. Use this resource as a formative assessment tool during one-on-one conferences. Listen to how students justify their thinking to gauge their understanding of concepts and reasoning abilities.
12. After solving several sets, have students reflect on their thinking process: “How did your perspective change?” “What strategies helped you see new possibilities?” “When did you feel most confident in your reasoning?”

Additional Video Tutorials and Articles:

Seeking additional ways to incorporate WODB into your classroom? These videos and articles provide expert insights and practical guidance to help you get started.

• TeachersFirst Review: Which One Doesn’t Belong?
• Video: Which One Doesn’t Belong? – Classroom Activity
• Video: Math Routines – Which One Doesn’t Belong?

Whether you use Which One Doesn’t Belong? as a daily warm-up or a formative assessment tool, this routine offers endless possibilities for meaningful learning. We’d love to hear how you’re using it—share your favorite activities, student insights, or creative twists in the comments below!