##
* *Reflection: Safety
Playing Teacher - Checking Our Work - Section 3: Independent Practice

I didn't want any one child to feel uncomfortable that someone was criticizing their work so I chose to review their work from a previous day and choose examples of common mistakes to complete the page. I filled in the blank page with different types of mistakes such as adding when I should subtract, and adding the tens as ones in the problem, or adding the ones as hundreds. I told students it was an old page that someone had done last year that I had not corrected. Students felt safer correcting an anonymous paper. They were willing to risk finding if the problem was incorrect because they didn't know who did it. Protecting their privacy with their work is important here. I want students to take the time to make sense of and solve the problems (MP1), rather than worry if someone will laugh at them for a mistake they made.

It was interesting that several of the students who can manipulate larger numbers were more willing to just assume the problem was right if the math was right, even without looking at the problem to see what it was asking. (reasoning abstractly MP2). They checked the math but not the words.

The students who struggle more with math were more likely to really read the problem and then try to see if the math matched what they were thinking. This may be because for these children, math is not automatic. They had watched the example and applied it to what they were supposed to do while the students who do math easily, just glanced at the math, and said yup the math is good so it is right. Often these brighter students need to be encouraged to show their work and to go beyond doing everything in their heads because at some point, they are going to need to be able to work through the process because the numbers will be too large to manipulate in their heads.

*Looking Carefully*

*Safety: Looking Carefully*

# Playing Teacher - Checking Our Work

Lesson 2 of 12

## Objective: SWBAT compare their work to comparison problems for accuracy, and explain why their addition or subtraction strategies worked.

## Big Idea: Students need to be able to explain the strategies they use to solve problems, and also they must understand the importance of checking their own work.

*60 minutes*

#### Warm Up

*15 min*

I put the following problem and solution on the board.

*I am 65 inches tall. My friend is 75 inches tall. How much taller is my friend than me? 65 + 75 = 5+5 = 10, and 6+ 7 = 13 and because 10 + 13 = 23, my friend is 23 inches taller than me.*

I ask students to look at my work. *What do you notice about my work?*

I listen as students make suggestions about what is correct or incorrect about my work. When we finally come to a consensus that I added, when I should have subtracted, I ask how I might have known what to do?

If no child suggests looking at the words that might help me (in my class we call them the *street sign* words math street signs.docx), I will lead students to look at the chart we made earlier which displays key words that help me to know which operation to use.

#### Resources

*expand content*

#### Teaching the Lesson

*15 min*

I tell students that today they will at some solutions from their classmate's practice page from yesterday’s lesson. I copied some of the solutions from different partnerships – some correct and some incorrect, for students to work with, onto a separate document for this lesson.

I tell students that they will be the teacher, and they need to correct this student work on their own. I alert them that some of the problems may be correct, and some may be incorrect. Students are told to mark work as correct, and redo problems or circle any place where they think there might be a mistake. They should be ready to defend their corrections. I tell them they will have 15 minutes to go over the work and then they will partner up with others to defend their corrections.

I ask for a student to repeat the directions as this is something we have not done before and I want to check for understanding before I let students work independently.

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#### Independent Practice

*15 min*

Students work for 15 minutes independently correcting the papers they have (which are copies of some of the student work from yesterday’s lesson that I have copied onto a master page so no one's work is being shared).Student Work I purposely chose examples that are incorrect in one way, such as the person added where they should have subtracted, or they did not attend to place value to see if students could reason abstractly and quantitatively about the problems as they try to make sense of what they need to do (MP 1 and MP2).

As students are working, I circulate around the room listening as students explain their thinking. Deciding Which is Correct

*expand content*

#### Closing

*15 min*

Today’s closing is longer that usual because I will ask students to critique each other’s solutions. (MP3). I ring the bell and tell students that I am going to partner them into groups of 4. They will bring their papers and compare what they have found as they corrected the papers. They will need to discuss any problem that all 4 did not agree on. They should work problem by problem, see if all 4 people agreed on whether the answer was right or not, and then if it was not right, how did they solve it, what can they see that the person might have done incorrectly, and what did they do to find the correct answer?

I give students about 15 minutes to discuss the problems. I circulate during this time to listen to student thinking, and to provide support as needed.

*expand content*

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- UNIT 1: What and Where is Math?
- UNIT 2: Adding and Subtracting the Basics
- UNIT 3: Sensible Numbers
- UNIT 4: Sensible Numbers
- UNIT 5: Everything In Its Place
- UNIT 6: Everything in Its Place
- UNIT 7: Place Value
- UNIT 8: Numbers Have Patterns
- UNIT 9: Fractions
- UNIT 10: Money
- UNIT 11: The Numbers Are Getting Bigger
- UNIT 12: More Complex Numbers and Operations
- UNIT 13: Area, Perimeter and More Measurement
- UNIT 14: Length
- UNIT 15: Geometry
- UNIT 16: Getting Ready to Multiply
- UNIT 17: Getting Better at Addition and Subtraction
- UNIT 18: Strategies That Work

- LESSON 1: Where is the Question
- LESSON 2: Playing Teacher - Checking Our Work
- LESSON 3: Estimation - an introduction
- LESSON 4: Using Models to Add and Subtract
- LESSON 5: Comparing Temperatures a Science and Math Exploration Part I
- LESSON 6: Comparing Temperatures A Math and Science Comparison Part II
- LESSON 7: Checking Subtraction
- LESSON 8: Introducing the Addition Algorithm
- LESSON 9: Addition Algorithm Rote or Understanding
- LESSON 10: Adding Repetitive Sets of Numbers
- LESSON 11: Adding and Subtracting in Columns
- LESSON 12: Getting Better At Addition and Subtraction Final Project