Module 1 Lesson 5. Group Counting Divide equal groups How many groups are there? How many are there in Each group? Say the total as a repeated addition.

Module 1 Lesson 5Understand the meaning of the

unknown as the number of groups in division.

Group Counting

• Let’s skip count by 2s forwards and backwards to 20. Remember to watch my hands to see if I change directions.

• Let’s skip count by 3s forwards and backwards to 21. Remember to watch my hands to see if I change directions.

Divide equal groups

How many groups are there?

How many are there in Each group?

Say the total as a repeated addition sentence.

Write a division sentence for 10 divided into 2 equal groups.

There are 2 groups

There are 5 in each group

5 + 5 = 10

10 ÷ 2 = 5

Divide equal groups

How many groups are there?

How many are there in Each group?

Say the total as a repeated addition sentence.

Write a division sentence for 8 divided into 4 equal groups.

There are 4 groups

There are 2 in each group

2 + 2 + 2 + 2 = 8

8 ÷ 4 = 2

Problem of the Day

Stacey has 18 bracelets. After she organizesthe bracelets by color, she has 3 equal groups.How many bracelets are in each group?

Before we start

• You need to have:• 18 counters• Pencil• Dry erase board/math notebook

• Thumbs up once you have everything you need.

Concept Development: Problem 1:

Next weekend, my friend Christy is having a party. Eighteen people are coming. I told her I’d help her set up tables. We know that 6 peoplecan sit at each table, but we’re not sure how manytables we’ll need. Turn and talk to a partner – what

information do Christy and I already have? So we know the size of the groups (6)And the total amount of people coming.

What information DON’T we know?

We don’t know the number of tables we will need.Tables are like groups – we don’t know how many groups we will need.

Next weekend, my friend Christy is having a party. Eighteen people are coming. I told her I’d help her set up tables. We know that 6 peoplecan sit at each table, but we’re not sure how manytables we’ll need.

Let’s use counters to show the problem and check our thinking. Each of you has 18 counters, 1 for each person coming to the party. Put them into groups of 6. Thumbs up when you’re done.

Do you still agree we know the total and the size of each group?

What else did we find out? Did we answer our question? How many tables we will need?

YES!

18 ÷ 6 = 3How does this number sentence relateto the problem we just solved?

POSSIBLE ANSWERS: • It shows that we divided. • We knew the total, 18 people. We

divided them into groups with 6 people. Then, we figured out that meant 3 groups of people.

• We divided the total by the size of the group and found the number of groups.

Next weekend, my friend Christy is having a party. Eighteen people are coming. I told her I’d help her set up tables. We know that 6 peoplecan sit at each table, but we’re not sure how manytables we’ll need.

Look back at your work from today’s Application Problem.

With a partner, compare the steps you took to solve both the bracelet problem and the party problem.

Notice the number sentences too.

Next weekend, my friend Christy is having a party. Eighteen people are coming. I told her I’d help her set up tables. We know that 6 peoplecan sit at each table, but we’re not sure how manytables we’ll need.

Stacey has 18 bracelets. After she organizesthe bracelets by color, she has 3 equal groups.How many bracelets are in each group?

I’m hearing you notice that the unknown was differentin each problem. We divide when we want to find thesize of the groups or the number of groups.

Quick practice Problem!

14 ÷ 7 = __________ Let’s say that 7 is the size of our groups – what will our unknown represent?

The number of groups. Draw a number bond to help find our unknown. Thumbs up when you’re finished.

2

Problem 2Christy plans to buy 15 burgers. Threeburgers come in each pack. How many packs should she buy?

Whisper to a partner what the numbers 15and 3 represent in this problem.

15 is the total number of burgers

3 is the numbers of burger in each pack

Is the unknown the number of groups or the size of the group?

The number of groups

On your personal white board or in your math notebooks, write the equation you would use to find how many packs to buy.

15 ÷ 3 = _____

p

• Let’s draw to find out how many packs of burgers Christy needs to buy.

Christy plans to buy 15 burgers. Threeburgers come in each pack. How many packs should she buy?

15 ÷ 3 = _____

How many packs doesChristy need?

5 packs of burgers

5

Let’s write the total number of burgers under eachpack. 3 6 9 12 15

WHY did we stop at 15?

What connection can you make between this and our group counting at the beginning of the lesson? Count by threes with me,

and track the number of threes on your fingers.

How many three did we count?

Skip-counting also shows us that Christy needs 5 packs of burgers.

PROBLEM SET