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Activity 1

Standards Alignment

Building On

Addressing

Building Toward

Instructional Routines

MLR7 Compare and Connect

Materials

To Gather

Connecting cubes in towers of 10 and singles Tools for creating a display

Activity Narrative

The purpose of this activity is for students to add and subtract within 20. Students are encouraged to find sums and differences in as many different ways as they can. They record their thinking and then do a Gallery Walk to look at their classmates’ work. Set-up for the Gallery Walk by putting all the posters for a specific expression together. The Activity Synthesis focuses on how decomposing a number to lead to a ten can be a helpful method when subtracting within 20 (MP7).
This activity uses MLR7 Compare and Connect. Advances: representing, conversing.

Launch

Groups of 2
Give each group tools for creating a visual display and access to connecting cubes in towers of 10 and singles.

Activity

MLR7 Compare and Connect

Read the Task Statement.
“Create a visual display that shows your thinking about each expression. You may want to include details such as drawings, numbers, words, or equations to help others understand your thinking.”
7 minutes: partner work time
“Now we will do a Gallery Walk so you can look at your classmates' work. Look for ways that their work is the same and different.”
7 minutes: Gallery Walk

Circle 1 addition expression and 1 subtraction expression.

Find the value of the expressions in as many different ways as you can.

Show your thinking using drawings, numbers, or words.

Student Response

to access Student Response.

Advancing Student Thinking

Activity Synthesis

“What is the same and what is different about how you and your classmates added or subtracted?” (Some of us wrote equations. Some of us made 10 for the addition and subtraction expressions.)
Display , , .
“How did this student find the difference between 13 and 6?” (They broke 6 into 3 and 3. They took 3 from 13 to get to 10, and then took the other 3 away.)
“Why is it helpful to look for ways to get to a 10 when subtracting?” (Once you are at 10, it is easy to subtract another number because we know our ten facts.)

Activity 2

Standards Alignment

Building On

Addressing

Building Toward

Instructional Routines

None

Materials

To Gather

Connecting cubes in towers of 10 and singles Number Cards 0–10

Activity Narrative

The purpose of this activity is for students to practice adding and subtracting within 20. Students add to find the sum of two numbers, and either add or subtract to find the unknown addend when one addend and the sum are given.

MLR8 Discussion Supports. Synthesis: Invite students to take turns sharing which equation they would choose and why. Ask students to restate what they heard using precise mathematical language and their own words. Display the sentence frame:
“I heard you say . . . .” Original speakers can agree or clarify for their partner.
Advances: Listening, Speaking

Engagement: Develop Effort and Persistence: Differentiate the degree of difficulty or complexity. Begin by giving students a subset of the number cards with more accessible values, and then introduce the remaining cards once students have written equations for the first subset of cards.
Supports accessibility for: Attention, Conceptual Processing

Launch

Groups of 3
Give students number cards and access to connecting cubes in towers of 10 and singles.
“We are going to play a game called Heads Up. This game is played with 3 students.”
Demonstrate with two students. Ask each student to choose a card without looking at it and hold it up to their foreheads.
“My partners have each chosen a card. My job is to find the sum and tell my group. Each of my partners use the other player’s number and the sum to determine what number is on their head. Then we all write the equation that represents what we did.”
Demonstrate writing an equation to show how you found the sum of the two numbers.
Ask students how they would find the number on each player's head and record the equations.
“After each round, switch roles and play again.”

Activity

15 minutes: small-group work time

Write an equation for each round you play.

Round 1: ________________________________

Round 2: ________________________________

Round 3: ________________________________

Round 4: ________________________________

Round 5: ________________________________

Round 6: ________________________________

Student Response

to access Student Response.

Activity Synthesis

“During one round of Heads Up, Diego’s partner had a 3 on their card. Diego was told that the sum of their numbers was 12. What equations can Diego use to figure out what number is on his card?” ( or )
“Explain which of these equations you would use to find the unknown number.” (I would use because it is really easy to count back 3. I would choose , because I prefer adding. I would add 7 to get to 10 and then 2 more.)

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Lesson 3

Add and Subtract within 20

Warm-up

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Student Response

Advancing Student Thinking

Activity Synthesis

Activity 1

Standards Alignment

Building On

Addressing

1.OA.6

Building Toward

Instructional Routines

Materials

To Gather

Activity Narrative

Launch

Activity

Student Response

Advancing Student Thinking

Activity Synthesis

Activity 2

Standards Alignment

Building On

Addressing

1.OA.6

1.OA.8

Building Toward

Instructional Routines

Materials

To Gather

Activity Narrative

Launch

Activity

Student Response

Activity Synthesis

Lesson Synthesis

Standards Alignment

Building On

Addressing

1.OA.6

Building Toward

Advancing Student Thinking