I love using Number Talks and CGI strategies in my math class. We recently had our CGI trainer visit and she mentioned that you can also do Number Talks while clearing up math misconceptions. I loved the idea and decided to give it a try when we were learning subtraction.
With subtraction, one of the misconceptions I noticed, was that students seemed to think when you regrouped you just put the number there. For example, if you were regrouping 100 you just put 100 there and the tens that existed before just went away.  I noticed a few of my students doing this when regrouping with hundreds, tens, and ones so I decided to have a little math misconceptions talk.
I first wrote this problem below on the board. I told students this was the math work from a former student and I wanted them to look at it and see if they think they student got the answer correct or wrong. If they got the answer correct, then you need to figure out how you know that. If they did not get the answer correct, where did they make a mistake in their work. I posed this problem and gave students a few minutes of quiet think time.
After a few minutes of think time, I had the students turn and talk and discuss with their partner what they noticed. I had some students who thought the answer was correct and some who thought it was incorrect. I asked students who felt strongly about both to explain why they thought they were right.  The children who thought it was right were some of my students who were making that same mistake.  As they were explaining why it was right, I asked them – where did the 20 go that was already in the tens spot? I then had many aha’s around the room. I had a child who thought the answer was incorrect walk us through the problem and corrected the original work. I showed this in a different color so we could see the misconception.  See the new work below…

This was an amazing class discussion and I plan on having many more Math Misconception Number Talks. I think it’s important for students to always be thinking and observing their work and others when we are sharing out.  This is a great way to go over mistakes that you are seeing and it points it out in a way that doesn’t make the child feel bad.  It empowers them to see the mistake in someone else’s work (I always say a former student and make up a name) and then they are more likely to catch it themselves when they do it.
Do you use Number or Math Talks in your classroom? Comment below…

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• November 11, 2017 at 3:20 pm

Thanks for this great tip! I'm going to use this on Monday.

• November 11, 2017 at 8:01 pm

Thanks for sharing a very practical solutions. I am goind to try it.

• November 11, 2017 at 9:20 pm

You're welcome! I'm glad you found it useful!
Jordan