Eureka Math
3rd Grade
Module 1
Lesson 9
At the request of elementary teachers, a team of Bethel & Sumner educators met as a committee to create Eureka slideshow presentations. These presentations are not meant as a script, nor are they required to be used. Please customize as needed. Thank you to the many educators who contributed to this project!
Directions for customizing presentations are available on the next slide.
Customize this Slideshow
Reflecting your Teaching Style and Learning Needs of Your Students
Screen A
“pop-out”
Screen B
Icons
Read, Draw, Write
Learning Target
Think Pair Share
Individual
Partner
Whole Class
Small Group Time
Small Group
Personal White Board
Problem Set
Manipulatives Needed
Fluency
I can find related multiplication facts by adding and subtracting equal groups in array models.
Group Counting
5 x 2 = ____
Let’s skip count by twos to find the answer.
3 x 2 = ____
Let’s skip count by twos again to find the answer.
Group Counting
Let’s see how we can skip-count down to find the answer, too.
Start at 10 with 5 fingers, 1 for each two.
Repeat the process for 4 x 2.
Multiply by 2 Pattern Sheet
Group Counting
Let’s count by threes.
Count Up Count Down
Group Counting
Let’s count by fours.
Count Up Count Down
Forms of Multiplication
Represent this array as a repeated addition sentence using 5 as the size of the groups.
Forms of Multiplication
____ fours = _____
Complete the equation on your personal white board.
Forms of Multiplication
Write two multiplication sentences for 7 groups of 2.
Forms of Multiplication
18 = 6 x ___
Complete the equation on your personal white board.
Forms of Multiplication
5 threes = ____
Complete the equation on your personal white board.
Forms of Multiplication
5 threes + 1 three = ____ ones
Complete the equation on your personal white board.
Add two known smaller facts...
Slip the template into your board.
Cover part of the array with blank paper to show 5 rows of 3. Draw a box around the uncovered array.
Write and solve a multiplication sentence to describe it.
Add two known smaller facts...
Move the paper so that the array shows 7 x 3.
Shade the rows you added.
Write and solve a multiplication sentence to describe the shaded part of the array.
Add two known smaller facts...
How many threes are in 5 x 3?
How many threes did you add to make the array show 7 x 3?
7 threes = 5 threes + 2 threes
Add two known smaller facts...
7 x 3 = 5 x 3 + 2 x 3
Do you agree or disagree?
We already wrote totals for the two parts of our array. Let’s add those to find the total for the whole array.
Add two known smaller facts...
What is the total for 5 x 3?
What is the total for 2 x 3?
______ = 15 + 6
Say the total at the signal.
Add two known smaller facts...
Cover part of the array with blank paper to show 4 rows of 3. Draw a box around the uncovered array.
Write and solve a multiplication sentence to describe it.
Add two known smaller facts...
Move the paper so that the array shows 8 x 3.
Shade the rows you added.
Write and solve a multiplication sentence to describe the shaded part of the array.
Add two known smaller facts...
How many threes are in 4 x 3?
How many threes did you add to make the array show 8 x 3?
8 threes = 4 threes + 4 threes
Add two known smaller facts...
8 x 3 = 4 x 3 + 4 x 3
Do you agree or disagree?
We already wrote totals for the two parts of our array. Let’s add those to find the total for the whole array.
Add two known smaller facts...
What is the total for 4 x 3?
What is the total for 4 x 3?
______ = 12 + 12 (Just double the total)
Say the total at the signal.
Explain how we added to find 7 x 3 = 21 and 8 x 3 = 24.
Subtract two known smaller facts...
Draw a box around the array that shows 9 x 3. Notice that 9 x 3 is close to 10 x 3.
10 x 3 is easier to solve because we can count by tens to get the total .
Let’s do that now.
Subtract two known smaller facts...
What should we subtract to show 9 threes instead?
Subtract two known smaller facts...
10 threes - 1 three = ______ threes
10 threes = _______
1 three = _______
Subtract two known smaller facts...
30 - 3 = ______
Subtract two known smaller facts...
Draw a box around the array that shows 8 x 3. Notice that 8 x 3 is close to 10 x 3.
10 x 3 is easier to solve because we can count by tens to get the total .
Let’s do that now.
Subtract two known smaller facts...
What should we subtract to show 8 threes instead?
Subtract two known smaller facts...
10 threes - 2 three = ______ threes
10 threes = _______
2 three = _______
Subtract two known smaller facts...
30 - 6 = ______
Tell your partner how we used 10 x 3 to help us find the answer to 9 x 3 and 8 x 3.
Problem Set
Debrief
Exit Ticket