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* *Reflection: Adjustments to Practice
Let's talk addition! - Section 3: Number Talk whole number addition

In retrospect I would make a couple of changes to the way I do Number Talks like this one in the classroom. This was my first year trying out this format. I think Number Talks can have a huge impact on student learning over time. In the future I would treat them as an entire lesson. I think they work better as a regular routine part of the classroom. Number sense is understanding that is developed over time through repeated experiences making connections and paying attention to relationships. I think there are several different goals with number talks including eliciting and trying multiple methods, making comparisons & connections between methods, and making connections to the standard algorithm. All three of these may not be present in every single Number Talk.

Making a connection to the standard algorithm is an element I would add once students have had a chance to explore and compare multiple methods. When students have been directly taught the standard algorithm and "learned" it through repeated mimicry of the process they tend to make mistakes when they mix it up or forget parts of it. In this case I write the standard algorithm on the board and ask what part is usually the part where people get confused. Students usually identify "carrying" or regrouping as the point of confusion. Once we review that the "1" being carried represents the 10 from the 16 I ask them where that part of the problem shows up in their mental math models. This way students can use their invented algorithms which are at their level of comprehension to understand the algorithm better.

# Let's talk addition!

Lesson 7 of 9

## Objective: SWBAT share multiple methods to do mental addition of whole and rational numbers

*54 minutes*

#### Warm Up

*15 min*

Today's warm up is looking for mistakes in our math family's homework from last night (included in resources). I display wrong answers that I got by making common expected mistakes on the screen for them to look for in addition to disagreement amongst the group:

1) 390 2) 102 3) 25 , 2 , 1 4) 1 , 12 5) 5 6) 51 , 149 , 24 7) 37 , 67 8) 30 , 225 , 15

9) 270 , 70 10) 9 , 1

This was a process that we learned in a previous lesson ("conversation moves" lesson earlier in this unit ). Then I give them correct answers to check on a partners paper then work together to learn from their mistakes. I call this "growing their brain" time, because they are learning from their mistakes and the mistakes of others.

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I started this first number talk by telling students briefly about why we will be doing them, that I want them to let go of the idea of looking for the "one right way" and try to pay more attention to their intuition about the number relationships. I want them to let go of the years of negative self talk about math. I have them pack everything up and use only their beautiful brains. I remind them to stay silent while working the problems mentally so everyone can concentrate. They signal silently to me without raising hands up to avoid distraction and intimidation. Thumbs up means "I have a solution", "pointer finger means I am working on a strategy, but I don't have a solution yet", "two fingers means I have two strategies".

The problem string I used for this first number talk was:

57 + 10

57 + 9

57 + 19

57 + 49

46 + 99

215 + 495

4.9 + 3.2

We did one problem at a time. I asked for solutions first, then strategies. My goal is to highlight multiple methods: Molly, Mei Lin, John, & Angelina each share different methods. I modeled their methods numerically as well as on an open number line. I also put their name next to it to give them some ownership and so others could easily reference the methods of others.

You will hear a boy, Brandon, off camera disagreeing with his first answer so I give him the first oportunity to explain what he had been thinking that caused the error and then his strategy for arriving at his new answer. Throughout the video you will see Angelina persists in using the counting on strategy until 57 + 49 when she says "oh, I can't use my strategy on this one" and tries one of the other ones she's seen from her peers (although she doesn't let go of counting completely).

At one point I shushed Jose only to find out on the video that he was so excited about being able to do the problem in his head that he wanted to talk about it with his math family. One special ed student in the corner was celebrated for sharing the correct solution. Too bad we can't see her face in the video! This was a girl who had her head down or was looking away during the first few problems and had already demonstrated within the first week of class that she had no confidence in her math ability.

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##### Similar Lessons

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- UNIT 1: Order of operations & Number properties
- UNIT 2: Writing expressions
- UNIT 3: Equivalent Expressions
- UNIT 4: Operations with Integers
- UNIT 5: Writing and comparing ratios
- UNIT 6: Proportionality on a graph
- UNIT 7: Percent proportions
- UNIT 8: Exploring Rational Numbers
- UNIT 9: Exploring Surface Area
- UNIT 10: Exploring Area & Perimeter