# Lesson 2

## Warm-up: Number Talk: 2 or 3 More (10 minutes)

### Narrative

The purpose of this Number Talk is to elicit strategies and understandings students have for adding 2 or 3 more. These understandings help students develop fluency and will be helpful later in this lesson when students count on to add.

In this activity, students have an opportunity to notice and make use of structure (MP7). They may see patterns in the structure of the expressions by noticing that when an addend changes by one the sum changes by one.

### Launch

• Display one expression.
• “Give me a signal when you have an answer and can explain how you got it.”
• 1 minute: quiet think time

### Activity

• Keep expressions and work displayed.
• Repeat with each expression.

### Student Facing

Find the value of each expression mentally.

• $$4 + 2$$
• $$5 + 2$$
• $$5 + 3$$
• $$6 + 4$$

### Student Response

For access, consult one of our IM Certified Partners.

### Activity Synthesis

• “Did anyone approach the problem in a different way?”

## Activity 1: More Shake and Spill (15 minutes)

### Narrative

The purpose of this activity is for students to solve Put Together, Total Unknown story problems through a context they are familiar with—the game Shake and Spill. To launch the lesson, the teacher plays a round of the game with students and reminds students to draw a box around the number in the equation that answers the question.

As students find sums, they relate addition to counting on and may apply what they know about the commutative property. Some of the story problems have the smaller addend first to encourage students to consider this property (MP7). Students should make sure that the answer to each question is clear in their representations.

In the activity synthesis, use physical counters as well as students’ representations to compare the two counting on methods.

MLR6 Three Reads. Keep books or devices closed. To launch this activity, display only the problem stem, without revealing the question. “We are going to read this story problem three times.” After the 1st Read: “Tell your partner what happened in the story.” After the 2nd Read: “What are all the things we can count in this story?” Reveal the question. After the 3rd Read: “What are different ways we can solve this problem?”

### Required Materials

Materials to Gather

### Required Preparation

• Each group of 2 needs 10 two-color counters.
• Have one cup available to demonstrate Shake and Spill.

### Launch

• Groups of 2
• “Let’s play a round of Shake and Spill together.”
• Demonstrate Shake and Spill.
• “What equation can I write to represent the total number of counters?”
• 30 seconds: quiet think time
• Record responses.
• “What number in the equation represents the total number of counters?”
• Draw a box around the total in the equation.

### Activity

• 6 minutes: independent work time
• 4 minutes: partner discussion
• Monitor for students who find the sum of 2 and 8 by:
• counting all
• starting at 2 and count on 8
• starting at 8 and count on 2

### Student Facing

1. Priya is playing Shake and Spill.
She spills 7 red counters and 2 yellow counters.
How many counters did she spill in all?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

2. Tyler spills 5 red counters and 3 yellow counters.
How many counters did he spill in all?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

3. Clare spills 2 red counters and 8 yellow counters.
How many counters did she spill in all?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

4. Han spills 3 red counters and 6 yellow counters.
How many counters did he spill in all?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

### Student Response

For access, consult one of our IM Certified Partners.

### Activity Synthesis

• Invite previously identified students to share in the sequence above.
• “How are these methods the same? How are they different?” (They are the same because they all add 3 and 6 and get 9. They all counted to get the answer. They are different because they counted different amounts. The first one counted all of the counters. The second counted 6 counters and the third counted 3 counters.)

## Activity 2: Are They Both Right? (10 minutes)

### Narrative

The purpose of this activity is for students to analyze representations of the work of two students who counted on. Each student chose a different addend to count on from, which illustrates the commutative property. Methods are represented and students are asked to explain why both methods are correct using precise mathematical language (MP6).

### Required Materials

Materials to Gather

• Groups of 2

### Activity

• 2 minutes: quiet think time
• 3 minutes: partner discussion

### Student Facing

Kiran and Clare are finding the value of $$2+ 7$$.

Kiran counted on from 2.

$$2 + 7 = \boxed{9}$$

Clare counted on from 7.

$$7 + 2 = \boxed{9}$$

How can both methods be correct?
Show your thinking using drawings, numbers, or words.

### Student Response

For access, consult one of our IM Certified Partners.

If students show that both equations are true without mentioning the 'add in any order' property, consider asking:

• “How do you know that both methods are correct?”
• “How can we use the same nine counters to move from the first method to the second?”

### Activity Synthesis

• Invite 2–3 groups to share their thinking.
• “Kiran and Clare started with different numbers, but they both got the same value. As long as we add the same two numbers, we can add them in either order. This is called the add in any order property.”
• “Which method do you like best? Why?” (I like adding up from the larger number since it is faster than adding up from the smaller number.)

## Activity 3: Practice Addition within 10 (10 minutes)

### Narrative

The purpose of this activity is for students to find the value of sums within 10. Students may apply what they learned about the commutative property and counting on. They may count on for certain equations, such as $$+1$$ or $$+2$$ equations as they can keep track easily, but count all for others. In the lesson synthesis, students return to the addition expressions cards they created in a previous lesson.

Action and Expression: Internalize Executive Functions. Invite students to plan a method, including the tools they will use, for finding the sum. If time allows, invite students to share their plan with a partner before they begin.
Supports accessibility for: Organization, Attention

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• Give students access to 10-frames and connecting cubes or two-color counters.

### Activity

• 5 minutes: independent work time
• 3 minutes: partner discussion

### Student Facing

Find the value of each sum.

1. $$7 + 2 = \boxed{\phantom{\frac{aaai}{aaai}}}$$
2. $$3 + 5 = \boxed{\phantom{\frac{aaai}{aaai}}}$$
3. $$\boxed{\phantom{\frac{aaai}{aaai}}} = 8 + 2$$
4. $$3 + 6 = \boxed{\phantom{\frac{aaai}{aaai}}}$$
5. $$5 + 2 = \boxed{\phantom{\frac{aaai}{aaai}}}$$
6. $$\boxed{\phantom{\frac{aaai}{aaai}}} = 4 + 4$$
7. $$2 + 6 = \boxed{\phantom{\frac{aaai}{aaai}}}$$
8. $$\boxed{\phantom{\frac{aaai}{aaai}}} = 1 + 9$$

### Student Response

For access, consult one of our IM Certified Partners.

## Lesson Synthesis

### Lesson Synthesis

“Today we saw different ways we can add numbers. Mai is practicing her sums to 10. She has $$7 + 2$$ in her ‘got it’ pile and $$2 + 7$$ in her ‘not yet’ pile. What would you tell Mai?” (If you know $$7 + 2$$, you also know $$2 + 7$$.) You can change the order of the numbers and get the same value.

Give students access to their addition cards sorted into ‘got it’ and ‘not yet.’ “Look through your ‘not yet’ cards. If you just know the sum, move it to your ‘got it’ pile. If you still need practice with a sum, keep it in your ‘not yet’ pile.”

## Cool-down: How Does it Help? (5 minutes)

### Cool-Down

For access, consult one of our IM Certified Partners.