##
* *Reflection: Developing a Conceptual Understanding
Addition and Subtraction Carnival Day 2 - Section 3: Center Time

After our discussion of 12 (The Number of the Day), I realized that some students were still struggling with the idea of the equal sign being at the beginning of the equation as well as toward the end. So, I put out a few number scales. Each scale had an equal sign near the fulcrum. I told the students they could choose a number and then try to find multiple ways to create the starting number. Watch the video in this section's resource to see a demonstration of this activity.

# Addition and Subtraction Carnival Day 2

Lesson 10 of 11

## Objective: SWBAT generate equivalent expressions for a number. SWBAT use numbers and standard notation to record. SWBAT use know strategies to solve story problems.

### Thomas Young

## Big Idea: Why stop a good thing? Students will continue to have the opportunity to challenge their addition and subtraction skills through a variety of activity choices.

*65 minutes*

### Thomas Young

I begin this part of the lesson by having the students try and guess the Number of the Day. I will write a number line on the whiteboard that ranges from 1-25 and gig ether two clues about the number. Then I will ask them to ask other questions to obtain more information about the number.

******Some other possible questions might be: *Does it have one digit? Does it have two digits? Is there a 5 in it? Is there a 1 in it?* You want to encourage students to ask questions that will narrow the set of possible numbers.

**"I want you to use figure out what Today's Number will be. I am going to give you two clues. One clue is that the number is greater than 3. The other clue is that it is less than 22."**

I will write the two clues as >3 and <22. I am using this as an opportunity to use the notation for greater than and less than. This was something that I introduced at the beginning of the year.

**"Who has another question they can ask to get more information about the unknown number?"**

I continue to do this until the number has been found. Today's number is 12.

I then ask the students "How can you represent 12?" I remind them that we can write the number 12, the word twelve, and draw 12 dots. Then I take suggestions from them. I had included a picture of the poster we made from this discussion (see the section resource).

#### Resources

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#### Center Time

*30 min*

The students will have a choice of a variety of addition and subtraction activities. All but one of them has been introduced in previous lessons.

1. Number of the Day: Using the handout in the section resource, the students find multiple ways of representing the number eight. They should be encouraged to use numbers and equations to represent their thinking. There is also a video in the resource section that demonstrates a student explaining their thinking during this activity. The Core Standards expect math students to model their thinking with mathematics. The idea being that mathematically proficient students can apply the mathematics they know to solve problems arising in everyday life, society, and the workplace. In early grades, this might be as simple as writing an addition equation to describe a situation (**CCSS.Math.Practice.MP4**). The students have an opportunity to demonstrate an understanding of the equal sign because they can notate 8+2=10 or 10=8+2 (CCSS.Math.Content.1.OA.D.7).

2. Story Problems: The students should continue working on the the problems they started two lessons ago. For those who finish and are ready for more challenging problems, I have included a new set of Challenge Problems in the section resource. It is expected that, by the end of the year, 1st grade students can use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem (CCSS.Math.Content.1.OA.A.1). These problems are allowing you to gain an idea of how each student is developing with their progress toward this standard.

3. Adding Dice Dots: This activity was introduced in the lesson Addition Rendition. Go to the Center Time section of the linked lesson to see the description and the resources needed.

4. Dice Subtraction: This activity was introduced in the lesson Ideas on Subtraction. Go to the Center Time section of the linked lesson to see the description and the resources needed.

Activities 3 & 4 both have students working on addition and subtraction fluency. The Core Standards expect first graders to relate counting to addition and subtraction and add/subtract within 20, demonstrating fluency for subtraction within 10 (CCSS.Math.Content.1.OA.C.5 & CCSS.Math.Content.1.OA.C.6). These two activities allow for the opportunity to work on these skills and take steps toward fluency.

#### Resources

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#### Lesson Wrap Up

*15 min*

I will gather the students back to the carpet area and ask them to face the document camera and screen. I have picked a few pieces of work that I wanted to have shared with the rest of the class. I have included three pieces and a video of a student sharing. I have chosen these pieces because they demonstrate two different ways for students to solve the same problem.

I want students to see examples of who to solve story problems and then have them connect the example to their own work. I will ask students if the example was similar or different then their own work.

I want my math practice to encourage students to Construct viable arguments and critique the reasoning of others. The idea being that mathematically proficient students understand and use stated assumptions, definitions, and previously established results in constructing arguments. I want them to have the ability to make conjectures and build a logical progression of statements to explore the truth of their conjectures. I also want them to be able to analyze situations by breaking them into cases, and can recognize and use counterexamples, and to justify their conclusions, communicate them to others, and respond to the arguments of others (**CCSS.Math.Practice.MP3**). This activity is an example what this would look like in 1st grade. The students are comparing and contrasting ideas, finding other ways of looking at an idea, and understanding that their are multiple ways to the solution of the problem.

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- UNIT 1: Counting Quantities
- UNIT 2: Working with Numbers, Operations, and Story Problems
- UNIT 3: Counting & Comparing
- UNIT 4: Blending
- UNIT 5: Building Numbers
- UNIT 6: Shapes Within Shapes
- UNIT 7: Data and Analysis
- UNIT 8: Non Standard Measuring
- UNIT 9: Shapes Within Shapes
- UNIT 10: Working with Numbers, Operations, and Story Problems
- UNIT 11: The Number 10 and the Addition and Subtraction Concept
- UNIT 12: The Ten Concept: Counting On and Off the Decade and Knowing 10 More/ 10 Less
- UNIT 13: Fraction Action Lessons
- UNIT 14: Counting by Groups
- UNIT 15: Complements of 10 and 20
- UNIT 16: Money!
- UNIT 17: Shapes, Blocks, and Attributes
- UNIT 18: Reviewing Data Collecting and Graphing

- LESSON 1: Counting the Total
- LESSON 2: Finding the Hidden Addend
- LESSON 3: Combinations, Day 1
- LESSON 4: Combinations, Day 2
- LESSON 5: Addition With Dice Dot Patterns
- LESSON 6: The Addition Rendition
- LESSON 7: Counting From A Number
- LESSON 8: Story Problems Involving Addition
- LESSON 9: Addition and Subtraction Carnival
- LESSON 10: Addition and Subtraction Carnival Day 2
- LESSON 11: Assessing Counting