Lesson 4

Sums of 10

Warm-up: True or False: Equal Expressions (10 minutes)

Narrative

The purpose of this True or False is to elicit understanding students have for the equal sign. It will also be helpful later when students generate equivalent expressions.

In this activity, students have an opportunity to look for and make use of structure (MP7) because they apply the commutative property to determine whether the equations are true or false.

Launch

• Display one statement.
• “Give me a signal when you know whether the statement is true and can explain how you know.”
• 1 minute: quiet think time

Activity

• Share and record answers and strategy.
• Repeat with each equation.

Student Facing

Decide if each statement is true or false.
Be prepared to explain your reasoning.

• $$3 + 5 = 8$$
• $$6 + 3 = 8$$
• $$3 + 5 = 5 + 3$$

Student Response

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Activity Synthesis

• “How can you justify your answer without finding each sum?” (If $$3 + 5 = 8$$, then I know $$6 + 3$$ can't be 8. I know $$3 + 5 = 5 + 3$$ because of the add in any order property.)

Activity 1: Shake and Spill: 10 Counters (10 minutes)

Narrative

The purpose of this activity is for students to decompose 10 in different ways through a familiar game, Shake and Spill. During the synthesis, the teacher records equations that students found during the activity, and students make connections between equations.

Required Materials

Materials to Gather

Materials to Copy

• Shake and Spill Stage 3 Recording Sheet Grade 1

Launch

• Groups of 2
• Give each group a cup, 10 two-color counters, and two recording sheets.

Activity

• “Today you will play Shake and Spill with 10 counters. When you write the equation to represent your counters, make sure it shows how many red counters and how many yellow counters you got.”
• 5 minutes: partner work time

Activity Synthesis

• Display six red counters and four yellow counters.
• “Here are the counters from a round of Shake and Spill. There are six red counters and four yellow counters. What equations can I write to represent the counters?” ($$6 + 4 = 10$$ and $$4 + 6 = 10$$)
• “Why do both equations represent the counters?” (You can start with the red or start with the yellow and there are still 10 total counters.)

Activity 2: All The Ways To Make 10 (15 minutes)

Narrative

The purpose of this activity is for students to justify that they have found all the ways to make 10. Students are given access to 10-frames and two-color counters to construct their argument (MP3). Students notice that there are patterns in the numbers in the expressions and how the addends change.

Some students may just start writing equations or placing counters in the 10 frame randomly. Other students may have a systematic way to find combinations such as placing 10 of one color, such as red counters, on the 10-frame and flipping one counter at a time to yellow (MP6).

MLR8 Discussion Supports. Synthesis: Display sentence frames to support whole-class discussion: “I knew I found all the ways because . . . . ” and “First, I _____ because . . . .”
Action and Expression: Internalize Executive Functions. Invite students to plan a method, including the tools they will use, for finding all the ways to make 10. 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, two-color counters, and yellow and red crayons.

Activity

• “You will have some time to work on this problem on your own, and then share your thinking with a partner.”
• 5 minutes: independent work time
• “Each student will have two minutes to prove to your partner that you have found all the ways to make 10. Your job as a partner is to listen and ask questions if you have any.”
• 2 minutes: partner discussion
• “Switch roles.”
• 2 minutes: partner discussion
• Monitor for students who have a systematic way to find all the combinations to share during lesson synthesis.

Student Facing

1. Show all the ways to make 10.

2. How do you know that you have found all the ways?
Be ready to explain your thinking in a way that others will understand.

Student Response

For access, consult one of our IM Certified Partners.

If students identify different ways to make 10 in random order, consider asking:

• “Can you use two-color counters to show me that these two numbers make 10?”
• “How can you change just one counter to make 10 in a different way?”

Activity Synthesis

• Invite previously identified students to share.
• “How do you know that you found all of the ways.” (I started by filling my 10-frame with red counters and then flipped over the first red counter to make it yellow. That was $$1 + 9$$. I kept flipping over a one red counter at a time to make it yellow and kept writing expressions.)

Activity 3: Centers: Choice Time (15 minutes)

Narrative

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 10. Students choose from any stage of previously introduced centers.

• Number Puzzles
• Check it Off
• Find the Pair

Required Materials

Materials to Gather

Required Preparation

• Gather materials from previous centers:
• Number Puzzles, Stage 1
• Check It Off, Stages 1 and 2
• Find the Pair, Stage 2

Launch

• Groups of 2
• “Now you are going to choose from centers we have already learned.”
• Display the center choices in the student book.
• “Think about what you would like to do.”
• 30 seconds: quiet think time

Activity

• Invite students to work at the center of their choice.
• 10 minutes: center work time

Choose a center.

Number Puzzles

Check it Off

Find the Pair

Activity Synthesis

• “What method do you use most often to find the value of sums you do not yet know?”

Lesson Synthesis

Lesson Synthesis

“Today we found all the ways to make 10.”

Display $$2 + 8 = 10, 3 + 7 = 10,$$ $$4 + \boxed{\phantom{\frac{aaai}{aaai}}} = 10$$
“Today we found all the ways to make 10. What is the value that makes this equation true? How do you know?” (6. The 4 is one more than the 3 in the other equation, so the 7 needs to be one less.)

Cool-down: Unit 3, Section A Checkpoint (0 minutes)

Cool-Down

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