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How to Start A Math Fight- Round 2 - How to build productive math discussion and discourse into your daily routine.

By Jon Orr posted 03-18-2019 08:48


Let’s start up round 2 of How To Start a Math Fight: Building productive math discussion and discourse into your daily routines. In Round 1 of this series I clarified that a math fight is centered around students TALKING about their mathematical thinking. From my experience, having students regularly discuss, argue, defend, justify ideas using mathematics helps them understand topics more deeply.

We can create these rich discussion moments in our classrooms by carefully planning three kinds of moments:

In Round 1 I shared a few examples of how to create out-loud thinking moments. In this post I’ll focus on why we should create moments of controversy and indecision, what resources we can use to make these moments, and how to facilitate them in your classroom.

Why we should create moments of controversy.

Creating moments of controversy in your class can look and sound very different from day-to-day and lesson-to-lesson. However, what’s common is that in each moment of controversy students have to make a choice or take a stand and then justify that choice among their peers. What I love most about placing my students in situations where they have to take a stand is how I get a glimpse into their thinking process. By simply asking them to make a choice and allowing them to explain their reasoning, it gives me a “giant bay window - and recently windexed! - view” into their understanding and possible misconceptions. By listening, I’m formatively assessing what that student understands about the ideas in the task and where I can help them the most.

How to create moments of controversy?

Here are three web resources that I think nail it when it comes to creating moments where students have to take a stand, and justify and defend their reasoning.

Would You Rather Math. (

HOW: Visit and choose a prompt to give to your class. Ask your class “Would you rather option A or option B?” Have a class discussion by taking a poll. Allow your class to work in pairs or groups of 3 to come up with math evidence to support a choice. Share selected student reasoning to support the two options.


Insist that your students take a “gut check” to begin. Have them choose one of the two options without using mathematical reasoning. Initiate a class discussion to share their initial reasoning. When a student shares their reasoning their classmates may be in disagreement. Encourage this productive discussion.

Here’s a sample prompt from the site. Use your downloaded placemat from Round 1 to make your gut check and then justify it!

jellybeans.jpg?w=960 Thanks to John Stevens for compiling all of these great prompts.

Which One Doesn’t Belong. (

HOW: Visit and select a prompt to show your class. Allow them to choose only one of the 4 choices and state why that one doesn’t belong with the rest.

WHERE’S THE FIGHT? Every one of the 4 option has a reason why it doesn’t belong with the rest. There are no wrong answers as long as a reason is chosen. You can instigate a fight by letting on that there is only one right answer. Have your students one-by-one share their choice and reasoning and sit back and let the discussions happen!

Here’s a sample prompt from the site. Use your downloaded placemat to show why your chosen item doesn’t belong with the other three. Thanks to Christopher Danielson’s Book Which One Doesn’t Belong: A Shapes Book and Mary Bourassa for creating the website.

Estimation 180 (

HOW: Visit and choose an estimate to show your class. Ask your students to estimate 3 numbers. A number that is too high, a number that is too low, and a number that is their best guess.

WHERE’S THE FIGHT? Ask students to tell the rest of the class which numbers are their “too high” and their “too low”. Let their disagreements happen. Students will say, “No way that is too high, my guess is bigger than that.” Tell the class you are looking for the closest estimate. Reveal the answer and let the cheers ring out!

Here’s a sample from the site. Use your downloaded placemat to record your too high, too low, best guess and reasoning. 

How many cheese balls will fit on the plate?

207_1_orig.jpeg Thanks to Andrew Stadel for creating all the prompts.

Look out for Round 3 of How To Start A Math Fight. We’ll continue with how to create moments of controversy with more great activities and resources.

You can download a How To Start A Math Fight Placemat to keep track of your learning in this 4 post series and the How To Start A Math Fight Quick Start GuideClick here to get the placemat and guide all in one.


You can find more from Jon Orr at



Twitter: @Mrorr_Geek