## Which One Doesn’t Belong? K-12 Critical Thinking and Problem Solving

**What it is: Which One Doesn’t Belong? **is a site I learned about from @TeamBaldwin today. This math site is for students of all ages and challenges them to look at a set of four images and determine which image doesn’t belong and justify their answer. The best part of this site is that each problem has multiple correct responses that can be justified. Students have to think through the differences that they see and then make logical decisions and be able to explain it to others. There are three different categories for Which One Doesn’t Belong including: Shapes, Numbers, Graphs and Equations.

**How to Integrate Which One Doesn’t Belong? in your classroom:** My favorite part about this site is that there are multiple answers for each set. Students can see how perspective and which attributes you are looking at can change the answer. The site is a great catalyst for critical thinking and problem solving in math (or any) class. Put a problem set up on a projector as a math class starter and ask your students to independently choose their answer and be ready to justify it. Then, as a class, discuss answers. After students have done this once, challenge them to find as many possible answers as they can independently before sharing responses. This site would be a great tie-in with the humanities to discuss perspective and vantage point. Even in something that feels as static as math, perspective can actually make any problem quite dynamic.

Yesterday, @TeamBaldwin used the site this way:

This is a class of kindergarten and first grade students! @michellek107 will be blogging more about the class experience on the class blog, Architects of Wonder if you’d like to read more.

**Tips:** The graphs and equations appear quite challenging, but even young students can begin making observations about the types of graphs that could lead to some higher-level math discussions.