# Lesson 4

More Work with 1 and 2

## Warm-up: Number Talk: Add 1 or 2 (10 minutes)

### Narrative

The purpose of this Number Talk is to elicit strategies and understandings students have for adding 1 or 2 to a given number. Students may use what they know about the count sequence to find the sums (MP7).

### 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 problems and work displayed.
• Repeat with each expression.

### Student Facing

Find the value of each expression mentally.

• $$6 + 1$$
• $$6 + 2$$
• $$8 + 1$$
• $$8 + 2$$

### Activity Synthesis

• “How are problems 3 and 4 the same? How are they different?” (They both start with 8. One adds one more and the other adds two more. The sums are 1 apart.)

## Activity 1: Introduce Five in a Row: Addition and Subtraction, Subtract 1 or 2 (20 minutes)

### Narrative

The purpose of this activity is for students to learn stage 2 of the center Five in a Row. In this stage, students subtract one or two from a number within 10. Some students may count back and some may count all then count back or remove 1 or 2 then count the remaining objects. Provide access to 10-frames and counters and encourage students to use them only if needed.

MLR8 Discussion Supports. Pair gestures with verbal directions to clarify the meaning of any unfamiliar terms such as “flip”, “across”, “diagonally”, and “5 in a row.”
Representation: Internalize Comprehension. Synthesis: Encourage students to make connections to the counting sequence and how they are choosing to subtract one or two.
Supports accessibility for: Organization, Memory, Attention

### Required Materials

Materials to Gather

### Required Preparation

• Each group of 2 needs a set of number cards 0–10.

• Each group of 2 needs a Five in a Row game board from the previous lesson.

### Launch

• Groups of 2
• Give each group a set of number cards, a game board, two-color counters, and access to 10-frames.
• “We are going to learn a new way to play, Five in a Row. Last time we played, we added one or two to the number on our card. This time, you will take turns flipping over a card and choosing whether to subtract one or two from the number. Then put a counter on the number on the game board. The first person to get five counters in a row wins. Remember, your counters can be in a row across, up and down, or diagonally.”

### Activity

• 10 minutes: partner work time
• As students work, consider asking:
• “How did you subtract?”
• “How did you decide whether to subtract 1 or 2?”
• Monitor for students who:
• represent the number, remove 1 or 2, count all that are left
• represent the number, remove 1 or 2, know how many are left without recounting
• count back 1 or 2
• use the counting sequence to find the difference

### Activity Synthesis

• “I have the number 8 and I want to subtract 2. How can I do it?”
• Invite previously identified students to share.
• “How are these methods the same? How are they different?” (They all take away 2. They solve in different ways.)

## Activity 2: Centers: Choice Time (20 minutes)

### Narrative

The purpose of this activity is for students to choose from activities that focus on counting up to 20 objects or adding and subtracting within 10. Students choose from the centers introduced in previous lessons as well as one introduced in the previous activity. If more than one stage of a center has been introduced, students choose from any of the stages. Students are encouraged to choose the center that will be most helpful for them at this time.

• Counting Collections
• Number Race
• Check it Off
• Five in a Row: Addition and Subtraction

### Required Materials

Materials to Gather

### Required Preparation

Gather materials from:
• Counting Collections, Stage 1
• Number Race, Stage 3
• Check it Off, Stage 1
• Five in a Row: Addition and Subtraction, Stages 1 and 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 first.”
• 30 seconds: quiet think time

### Activity

• Invite students to work at the center of their choice.
• 8 minutes: center work time
• “Choose what you would like to do next.”
• 8 minutes: center work time

### Student Facing

Choose a center.

Counting Collections

Number Race

Check it Off

Five in a Row: Addition and Subtraction

### Activity Synthesis

• “What was your favorite part of center time today? Why was it your favorite?”

## Lesson Synthesis

### Lesson Synthesis

Display the math community poster and read the student actions listed under “Doing Math.”

“Which of these did you do today? How did they help you in class?”

“Is there anything else we should add to the poster?”