MATH Lesson 12.13

LO: SWBAT multiply a two-digit number by a one-digit

number using the distributive property.

DOL: SW multiply a two-digit number by a one-digit

number using distributive property correctly on 4 out of 5

questions.

TEKS 3.4(G) Use strategies and algorithms, including the standard algorithm, to multiply a two-digit number by a one-digit number.
Strategies may include mental math, partial products, and the commutative, associative, and distributive properties.

11

Lesson Vocabulary

Factor(s)

22 x 5 = 110

Product

22 x 5 = 110

Distributive Property

22 x 5

(20 + 2) x 5

(20 x 5) + (2 x 5)

100 + 10

110

10

Define Me

Taylor solved the following multiplication expression 25 x 9 using
the distributive property.

25 x 9 =

20 + 5

( 20 x 9) + (5 x 9)

180 + 45 = 225

How would you define distributive
property?

The distributive property
is ___________.

12

Write the answer in standard form.

20 + 3

Write23in expanded notation.

Write the answer in standard form.

80 + 7

Write87in expanded notation.

13

Write the answer in standard form.

300 + 50 +8

Write358in expanded notation.

Write the answer in standard form.

400 + 7 + 90

Write497in expanded notation.

GET Strategy for Multiplication & Division

G: number of Groups
E: number of items in Each group
T: Total number of items

Multiplication

Division

G xE =T

T ÷ G = E

Ex G=T

T ÷E = G

When baking one large batch of cookies, Tamia uses 24
cups of flour. How many cups of flour does she need for
8 batches?

Let's read the story problem below.

16

When baking one large batch of cookies, Tamia uses 24
cups of flour. How many cups of flour does she need for 8
batches?

How can we represent the problem?

Let's represent the story problem below.

Let’s model this problem with a strip diagram. Draw with me on your board.

17

When baking one large batch of cookies, Tamia uses
24 cups of flour. How many cups of flour does she need
for 8 batches?

What operation would you use to solve this problem? Why?

Equation:

18

When baking one large batch of cookies, Tamia uses
24 cups of flour. Which expression shows a way to
determine the number of cups of flour she needs for 8
batches?

A. (2 x 8) + (4 x 8)
B. (24 x 8) + 24 x 8)
C. (20 x 8) + (4 x 8)
D. (40 x 8) + (2 x 8)

19

When baking one large batch of cookies, Tamia uses 24 cups of flour.
How many cups of flour does she need for 8 batches?

Teacher Exemplar

24

24

24

24

24

24

24

24

?

G: 8 batches
E: 24 cups of flour
T: ? cups of flour

Equation: 24 x 8 =

20

When baking one large batch of cookies, Tamia uses 24 cups of flour.
How many cups of flour does she need for 8 batches?

Teacher Exemplar

24 x 8

(20 + 4) x 8

(20 x 8) + (4 x 8)

160 + 32

192

Distributive Property

Tamia needs 192 cups of flour for
8 batches.

21

When baking one large batch of cookies, Tamia uses
24 cups of flour. Which expression shows a way to
determine the number of cups of flour she needs for 8
batches?

A. (2 x 8) + (4 x 8)
B. (24 x 8) + 24 x 8)
C. (20 x 8) + (4 x 8)
D. (40 x 8) + (2 x 8)

Answer Key

Mr. Brown and eight of his co-workers are combining
money to buy holiday presents for their assistant
principals. Each teacher contributed $45. How much
money did they collect for the presents?

Let's read the story problem below.

23

Mr. Brown and eight of his co-workers are combining money to buy
holiday presents for their assistant principals. Each teacher contributed
$45. How much money did they collect for the presents?

How can we represent the problem?

Let's represent the story problem below.

Let’s model this problem with a strip diagram. Draw with me on your board.

24

Mr. Brown and eight of his co-workers are combining money to buy
holiday presents for their assistant principals. Each teacher
contributed $45. How much money did they collect for the presents?

What operation would you use to solve this problem? Why?

Equation:

25

Mr. Brown and eight of his co-workers are combining money to buy
holiday presents for their assistant principals. Each teacher
contributed $45. How much money did they collect for the presents?

F. $305

G. $81

H. $486

J. $405

26

Mr. Brown and eight of his co-workers are combining money to buy
holiday presents for their assistant principals. Each teacher
contributed $45. How much money did they collect for the presents?

Teacher Exemplar

$45 $45 $45 $45 $45 $45 $45 $45 $45

?
G: 9 teachers
E: $45
T: ?

Equation: 45 x 9 =

27

Mr. Brown and eight of his co-workers are combining money to buy
holiday presents for their assistant principals. Each teacher
contributed $45. How much money did they collect for the presents?

Teacher Exemplar

45 x 9

(40 + 5) x 9

(40 x 9) + (5 x 9)

360 + 45

405

Distributive Property

The teachers collected $405 for
the presents.

28

Mr. Brown and eight of his co-workers are combining money to buy
holiday presents for their assistant principals. Each teacher
contributed $45. How much money did they collect for the presents?

F. $305

G. $81

H. $486

J. $405

Answer Key

29

Story Problem

Lupe is saving money for her family vacation. She saves $47 each
month. How much money will she save in 6 months?

Solve the story problem using the distributive property and partial
products.

30

Story Problem

The school store purchased 89 packs of notebooks. Each pack of
notebooks contains 6 notebooks.

How many notebooks did the school store purchase?

Solve the story problem using the distributive property and standard
algorithm.

31

Story Problem

The school store purchased 89 packs of notebooks. Each pack of
notebooks contains 6 notebooks.

How many notebooks did the school store purchase?

A.

102

B.

534

C.

484

D.

525

SW multiply a two-digit number by a one-digit number using distributive
property correctly on 4 out of 5 questions.

LO: SWBAT multiply a two-digit number by a one-digit
number using partial products and standard algorithm.

DOL: SW multiply a two-digit number by a one-digit
number using partial products and standard algorithm

correctly on 4 out of 5 questions.

TEKS 3.4(G) Use strategies and algorithms, including the standard algorithm, to multiply a two-digit number by a one-digit number.
Strategies may include mental math, partial products, and the commutative, associative, and distributive properties.

10

Who's right?

Alicia solved the following math expression, 46 x 9, using
partial products. Did Alicia solve the expression
correctly?

Alicia's Work

4 6
x 9
54 (9 x 6)
36 (9 x 4)

+

90

Alicia solved the
expression ______
because ______.

8

Do Now

Solve for this problem. Show your work.

While on vacation, Robin took thirty-seven
pictures at the zoo and twenty-five at the
museum.

If she later deleted twenty-nine of the
pictures, how many pictures from her
vacation did she still have?

11

Lesson Vocabulary

Factor(s)

22 x 5 = 110

Product

22 x 5 = 110

Standard Algorithm

22
x 5

Partial Product

22
x 5

110

10 (5 x 2)
100 (5 x 20)+

110

1

9 x 1 = ________

9 x 2 = ________

9 x 3 = ________

9 x 4 = ________

9 x 5 = ________

9 x 6 = ________

9 x 7 = ________

9 x 8 = ________

9 x 9 = ________

9 x 10 = _______

9 x 5 = ________

9 x 6 = ________

9 x 5 = ________

9 x 7 = ________

9 x 5 = ________

9 x 8 = ________

9 x 5 = ________

9 x 9 = ________

9 x 5 = ________

9 x 10 = _______

9 x 6 = ________

9 x 5 = ________

9 x 6 = ________

9 x 7 = ________

Multiply.

GET Strategy for Multiplication & Division

G: number of Groups
E: number of items in Each group
T: Total number of items

Multiplication

Division

G xE =T

T ÷ G = E

Ex G=T

T ÷E = G

Kim has 7 bags of candy. Each bag has 36 candies.

How many candies does Kim have?

Let's read the story problem below.

15

Kim has 7 bags of candy. Each bag has 36 candies. How many
candies does Kim have?

How can we represent the problem?

Let's represent the story problem below.

Let’s model this problem with a strip diagram. Draw with me on your board.

16

Kim has 7 bags of candy. Each bag has 36 candies. How many
candies does Kim have?

What operation would you use to solve this problem? Why?

Equation:

Kim has ________ candies.

17

Kim has 7 bags of candy. Each bag has 36 candies. How many
candies does Kim have?

Teacher Exemplar

36

36

36

36

36

36

36

?

Partial Products

Standard Algorithm

3 6
x 7
42 (7 x 6)
120 (7 x 30)
252

3 6
x 7

252

4

Kim bought 252 candies.

G: 7 bags
E: 36 candies
T: ? candies

Equation: 36 x 7 =

+

Tasha organized her tickets into an array. One of the
rows in Tasha's array is shown.

There are thirty nine rows in Tasha's array.

How many tickets does Tasha have in all?

Let's read the story problem below.

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Image by Clker-Free-Vector-Images from Pixabay

19

How can we represent the problem?

Let's represent the story problem below.

Let’s model this problem with a strip diagram. Draw with me on your board.

Tasha organized her tickets into an array. One of the rows in Tasha's array is
shown.

There are thirty nine rows in Tasha's array. How many tickets does Tasha have
in all?

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Image by Clker-Free-Vector-Images from Pixabay

20

Tasha organized her tickets into an array. One of the rows in Tasha's array is
shown.

There are thirty nine rows in Tasha's array. How many tickets does Tasha have in
all?

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Image by Clker-Free-Vector-Images from Pixabay

What operation would you use to solve this problem? Why?

Equation:

Tasha has _____ tickets.

21

Tasha organized her tickets into an array. One of the rows in Tasha's array is
shown.

There are thirty nine rows in Tasha's array. How many tickets does Tasha have in
all?

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Image by Clker-Free-Vector-Images from Pixabay

Teacher Exemplar

8

8

8

8

8

…

This is referencing a continuous number of

groups or rows, since there are 39 rows.

?

G: 39 rows
E: 8 tickets
T: ? tickets

Equation: 39 x 8 =

Row 1

22

Tasha organized her tickets into an array. One of the rows in Tasha's array is
shown.

There are thirty nine rows in Tasha's array. How many tickets does Tasha have in
all?

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Ticket

Image by Clker-Free-Vector-Images from Pixabay

Teacher Exemplar

Partial Products

Standard Algorithm

3 9
x 8
72 (8 x 9)
240 (8 x 30)
312

3 9
x 8

312

7

Tasha bought 312 tickets.

+

26

Story Problem

Ben has 34 bags. He put 6 party favors in each bag.

How many party favors are there in total?

Solve the story problem using partial products or standard algorithm.

27

Story Problem

Ben has 34 bags. He put 6 party favors in each bag.

How many party favors are there in total?

A.

42

B.

204

C.

40

D.

184

Ben has ______ party favors in total.

SW multiply a two-digit number by a one-digit number using partial
products and standard algorithm correctly on 4 out of 5 questions.