# Lesson 7

Count Large Collections

## Warm-up: What Do You Know About 103? (10 minutes)

### Narrative

The purpose of this What Do You Know About is to invite students to share what they know about and how they can represent the number 103. The warm-up allows students to share multiple ways to represent a number using tens and ones.

### Launch

• Display the number.
• “What do you know about 103?”
• 1 minute: quiet think time

### Activity

• Record responses.
• “How could we represent the number 103?”

### Student Facing

What do you know about 103?

### Activity Synthesis

• “What connections do you see between different representations?”

## Activity 1: Last Number Wins (15 minutes)

### Narrative

The purpose of this activity is for students to count within 120 starting at a number other than 1. Students stand in a circle and are given a “start” and “stop” number. As they count around the circle, each student says one number until they reach the “stop” number. The student who says the last number wins the round.

### Required Preparation

• Prepare a chart with these start and stop numbers:

Start

Stop

$$\phantom {0}67\\ \phantom {0}85\\ \phantom {0}90\\ 100$$

$$\phantom {0}80\\ \phantom {0}95\\ 105\\ 120$$

### Launch

• Groups of 5
• Display chart with “start” and “stop” numbers.
• “Today we are playing a new game called Last Number Wins. In this game your group will count from the ‘start’ number to the ‘stop’ number. The person to say the last number wins. Let’s play one round together. Our ‘start’ number will be 1 and our ‘stop’ number will be 43.”
• Arrange students in a circle and explain that each student says one number. Count to 43. The person who says “43” wins.

### Activity

• “When you play in your groups, use the ‘start’ and ‘stop’ numbers listed on the chart.”
• 8 minutes: group work time

### Activity Synthesis

• “Let’s play another round as a class.”
• Display the “start” number 100 and the “stop” number 120.
• “How did you know what number to say after 100?” (It’s one more than 100 so that is 101.)

## Activity 2: Count and Represent (15 minutes)

### Narrative

The purpose of this activity is for students to count a collection of between 90 and 120 objects. As students count, they apply what they have learned about grouping objects to make counting more efficient and accurate (MP6, MP7). Students may represent their count with different representations that they have worked with, including base-ten drawings, words ( _____ tens _____ ones), numbers, expressions, and equations.

Representation: Internalize Comprehension. Synthesis: Record students’ methods for counting the collection of objects on a display and keep visible during the next activity.
Supports accessibility for: Visual-Spatial Processing, Memory

### Required Materials

Materials to Gather

### Required Preparation

• Create collections of between 90 and 120 objects, such as connecting cubes, counters, centimeter cubes, paper clips, pattern blocks, or other objects, for each group of 2 students.

### Launch

• Groups of 2
• Give each group a collection of objects and access to double 10-frames, plates, and cups, or other tools that can be used to organize collections.
• “We have been practicing counting up to 120. Now we are going to count objects in a large collection. Work with your partner to decide how to organize, count, and represent your collection. You may decide to count the collection in different ways.”

### Activity

• 10 minutes: partner work time
• Monitor for students who represent their collection in different ways, including:
• drawing groups of ten objects and singles
• making a base-ten drawing to show tens and ones
• labeling their count to show counting all the tens, then the ones

### Student Facing

How many objects are in your collection?

Represent how many in as many ways as you can.

### Student Response

If students count by ones, consider asking:

• “How did you count your collection?”
• “How could you use groups of ten to help you organize this large collection?”

### Activity Synthesis

• Display previously identified student work.
• “How did this student count and represent their collection?” (They drew tens and ones, counted the number of tens, and added the ones.)
• “What is the same about these representations? What is different?” (One shows all of the objects and the other made a drawing of a ten instead of showing 10 objects.)

## Activity 3: How Many Cats? (10 minutes)

### Narrative

The purpose of this activity is to count an organized arrangement of images and write a number to represent the quantity. The arrangement is designed to encourage kids to count by 10 as each row, except the last, has ten cats. Students may determine the number of tens and ones (10 tens 8 ones is 108) or they may skip count the groups and count on by ones (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 101, 102, 103, 104, 105, 106, 107, 108).

MLR7 Compare and Connect. Synthesis: After all strategies have been presented, lead a discussion comparing, contrasting, and connecting the different approaches. Ask: “How are the strategies similar? How are the strategies different? What connections can you make between the strategies?”

• Groups of 2

### Activity

• 3 minutes: independent work time
• “Explain how you counted to your partner. If you got different answers, work together to figure out how many cats there are.”
• 3 minutes: partner work time
• Monitor for students who count by:
• circling groups of cats and then skip counting or adding them
• recognizing that first ten rows each have 10 cats

### Student Facing

How many cats are there?

There are ____________ cats.

Show your thinking using drawings, numbers, or words.

### Activity Synthesis

• Display student work that shows grouping in different ways.
• “How did they group the cats? How did it help them figure out how many there were?” (They circled 5 rows for 50 and another 5 rows, and knew that $$50 + 50 = 100$$. Then there are 8 more, which is 108.)

## Lesson Synthesis

### Lesson Synthesis

“Today we counted objects and images. How is counting a collection the same as counting images on paper? How is it different?” (They are the same because you can organize both into groups. They are different because you can’t move the images around into groups or piles however you want, but you can do that with real objects in a collection. With images, you can look for ways it may already be in groups or make your own by circling.)

“How did you use ten today to help you count? How was ten helpful?” (We organized our objects into groups of ten. Then we counted the tens. It helped us keep track when we had to count lots of things.)