What Would You Tell This Person?
It is important for students to understand that the purpose of this Warm Up is not to make fun of people who make mistakes in math...in fact, that is exactly the opposite of what kids need to be learning. Everyone can make mistakes. At the same time, it can be empowering and fun for students to find errors in other's thinking. Allowing students to find and discuss why they are mistakes as well as what they would tell the person to help them see their mistakes is great practice for communicating these ideas to others. Plus, not all of these are mistakes...but are possibilities for students to simply converse about the possible mathematics involved.