# Lesson 13

Center Day 3

## Warm-up: Choral Count: Count Back from 100 (10 minutes)

### Narrative

The purpose of this Choral Count is to invite students to practice counting backward by 1 and notice patterns in the count. These understandings help students develop fluency with the count sequence as well as the base-ten structure of numbers.

### Launch

• “Count backward by 1, starting at 100.”
• Record as students count.
• Stop counting and recording at 70.

### Activity

• “What patterns do you see?”
• 1-2 minutes: quiet think time
• Record responses.

### Student Response

For access, consult one of our IM Certified Partners.

### Activity Synthesis

• “Who can restate the pattern in different words?”
• “Does anyone want to add an observation on why that pattern is happening here?”

## Activity 1: Introduce Target Numbers, Add Two-Digit Numbers (20 minutes)

### Narrative

The purpose of this activity is for students to choose from activities focusing on two-digit numbers. Students are introduced to stage 3 of the Target Numbers center. Then students choose between that center or others previously introduced.

Students choose from any stage of previously introduced centers.

• Target Numbers
• Number Puzzles
• Mystery Number

### Required Materials

Materials to Gather

Materials to Copy

• Target Numbers Stage 3 Recording Sheet

### Required Preparation

• Gather materials form previous centers:
• Target Numbers, Stages 1-2
• Number Puzzles, Stages 1-4
• Mystery Number, Stage 1

### Launch

• Groups of 2
• “Today you will choose from centers we have already learned. One of the choices is to play Target Numbers in a new way. Just like last time, your target number is 95. You will roll two cubes to get your starting number. Then, on each turn, roll three cubes and choose one of the numbers to represent the tens and another number to represent the ones. Add the new number you made to your starting number and record your equation. Continue playing for six rounds to see who gets closest to 95 without going over.”
• Display the center choices in the student book.
• “Think about what you would like to do first.”
• 30 seconds: quiet think time

### Activity

• 8 minutes: center work time
• “Choose what you would like to do next.”
• 8 minutes: center work time

Choose a center.

Target Numbers

Number Puzzles

Mystery Number

### Activity Synthesis

• “What did you like about the centers you chose?”

## Activity 2: Introduce Five in a Row, Add within 100 with Composing (20 minutes)

### Narrative

The purpose of this activity is for students to choose from activities focusing on two-digit numbers. Students are introduced to stage 6 of the Five in a Row center. Then students choose between that center or others previously introduced.

Students choose from any stage of previously introduced centers.

• Five in a Row
• Get Your Numbers in Order
• Grab and Count

### Required Materials

Materials to Gather

Materials to Copy

• Five in a Row Addition and Subtraction Stage 6 Gameboard

### Required Preparation

• Gather materials from previous centers:
• Five in a Row, Stages 1-6
• Get Your Numbers in Order, Stage 1
• Grab and Count, Stage 2

### Launch

• Groups of 2
• “Now you will choose from other centers we have already learned. One of the choices is to play Five in a Row with a new gameboard. On this gameboard you will add 2 two-digit numbers that make a new ten.”
• Display the center choices in the student book.
• “Think about what you would like to do first.”
• 30 seconds: quiet think time

### Activity

• 8 minutes: center work time
• “Choose what you would like to do next.”
• 8 minutes: center work time

Choose a center.

Five in a Row