math unit 2 recalling multiplication facts

MATH UNIT 2RECALLING

MULTIPLICATION FACTS4TH GRADE

Choose the best term from the box.

breaking apart product factor multiples

In the number sentence 8 x 3 = 24, 8 is a _____.

In the number sentence 2 x 6 = 12, 12 is a_____.

191 + 67 = ( 191 + 9) + 58 is an example of using the _____ strategy.

Skip Counting

10, 12, 14, 16, ____

5, 10, 15, 20, ____

3, 6, 9, 12, ____

12, 16, 20, 24, ____

8, 16, 24, 32, ____

7, 14, 21, 28, ____

100, 80, 60, ____

13, 26, 52, 104, ____

40, 20, 10, ____

Look at each array. Circle groups of 3.

What multiplication fact does each array represent?

Nicholas is thinking of a whole number.

He multiplies the number by 5, but the

resulting answer is less than 5.

What number is he thinking about?

2-1 Patterns for Facts

What are the patterns for multiples

of 2, 5, and 9 ?

* A MULTIPLE is the product of any two whole numbers.

To find multiples of 2 all you need to do is skip count by 2s.

To find multiples of 5 all you need to do is skip count by 5s.

To find multiples of 9 all you need to do is skip count by 9s.

Skip count to find the number that comes next.

20, 25, 30, ____

36, 45, 54, ____

99, 88, 77, ____

1, 8, 15, ____

15, 30, 45, ____

Find the product.

* A PRODUCT is the answer to a multiplication problem.

9 x 1 = 3 x 8 = 5 x 4 = 4 x 2 =

5 x 7 = 2 x 3 = 6 x 5 = 9 x 7 =

6 x 3 = 0 x 12 = 9 x 3 = 4 x 6 =

How do you know that 13 is not

a multiple of 2?

__________________

What are all of the multiples of 2

up to 20?

Alyssa is sorting socks for her mom.

She has 9 pairs of socks. How many

socks does she have in all?

While most species of starfish have 5 arms, some species can have up to

40 arms. How many arms do 9 starfish have?

_______

How many arms would 6 starfish have?

_______

How many arms would 7 starfish have?

_______

Grace is working on her model train set.

She adds 9 pieces of track. Each

piece of track is attached with 4

screws. How many screws will she

need to attach the track?

Write the equation and solve.

Which is equal to 9 dollars and

9 nickels?

______ + ______ = $______

What is equal to 17 dollars and

12 dimes?

______ + ______ = $______

In wheelchair basketball, players use

sports chairs that have 2 large wheels

and 3 small wheels each. If there are

5 players, how many…

Large wheels? _____

Small wheels? _____

Large and Small wheels? _____

_____ + _____ = _____

Each pentagon shown below has

5 sides. How many sides are there

in all?

Strategy: skip count by 5s.

Write the equation (multiplication sentence)

_____ x _____ = _____

CHALLENGE

Can you write a 3 digit number that

when it is rounded to the nearest

ten or to the nearest hundred the

answer is the same?

2 – 2 Multiplication Properties

Multiplication Properties

How can properties help you multiply?

Commutative Property of Multiplication means that two numbers can be

multiplied in any order and the

product will be the same.

3 Groups of 2 = 6 2 Groups of 3 = 6

Zero Property of Multiplication

Any number multiplied by zero = zero

2 groups of 0

2 x 0 = 0

Identity Property of Multiplication

The product of any number and

one is that number.

1 Group of 7

1 X 7 = 7

In a soccer tournament, Ava’s

team scored zero goals in each game.

They played a total of 6 games.

Write a multiplication sentence to show

how many goals they scored in all.

Find each product.

0 x 5 1 x 6 4 x 7 6 x 3

1 x 5 7 x 0 3 x 9 0 x 8

0 x 3 9 x 4 2 x 7 6 x 5

1 x 1 4 x 0 1 x 9 4 x 5

Taylor has 6 packages of tennis balls.

How many packages of golf balls

would Taylor need so that she has

an equal number of golf balls and

tennis balls?

TYPE OF BALLNUMBER PER

PACKAGE

BASEBALLS 1

TENNIS BALLS 3

GOLF BALLS 6

If Brianna and three of her friends each bought one package of baseballs, how

many baseballs do they have in all?

TYPE OF BALLNUMBER PER

PACKAGE

BASEBALLS 1

TENNIS BALLS 3

GOLF BALLS 6

Ryan scored 4 goals in each of

3 soccer games. His friend Tyler

scored 3 goals in each of 4 soccer

games. Who scored the most goals?

Explain.

Mrs. B has 27 students in her ESOL

class. She wants to rearrange the

desks in equal groups. If the desks

are in 9 groups of 3 desks now,

what are other ways that she could

arrange the desks?

Draw different arrays to show arrangements of 24 desks.

2 - 3

Use known facts:

3 and 4 as FACTORS

James is replacing the wheels on

8 skateboards. How many wheels

does he need in all?

Use the DISTRIBUTIVE PROPERTY

to break apart facts into simpler

problems.

Find 10 x 4

Break the equation apart into

(5 x 4) + (5 x 4)

So 10 x 4 = ____

or

(10 x 3) + (10 x 1)

So 10 x 4 = ____

Use breaking apart to find each product.

3 x 4 7 x 6 9 x 2 4 x 7

8 x 4 5 x 3 6 x 4 3 x 7

5 x 8 7 x 9 8 x 6 5 x 9

The manatee is an endangered sea

mammal. A mother manatee is

three times as long as her baby.

How long is the baby manatee if the

mother is 12 feet long?

John, Noah, and their dads went to

the movies. Each ticket cost $7.

They also each spent $4 on snacks.

How much money did they all spend

at the movies?

In his last basketball game, Brandon

scored 15 points. Which of the

following is NOT a possible way he

could have scored his points?

5 three-point shots3 three-point shots and 2 three-point

shots

3 two-point shots and 2 one-point free

throws

5 two-point shots and 5 one-point free

throws

Lauren scored 6 two-point baskets

and 6 one-point free throws. Chloe

scored 6 three-point baskets. Explain

how you know each girl scored the

same total points in the game.

A botanist is growing a four-petal

pawpaw shrub. He counted 9 flowers

on the shrub. Which uses breaking

apart to find the total number of

petals on the pawpaw?

( 5 x 4 ) + ( 4 x 4 ) ( 9 x 4 ) + ( 9 x 4 )

( 9 + 4 ) x ( 9 + 4 ) ( 5 + 4 ) x ( 4 + 4 )

Using Know Facts: 6, 7, and 8 as FACTORS

Are there different ways to break

apart a fact?

Mrs. B’s class drew

a map of their town.

The map is 6 blocks

by 6 blocks. How many

square blocks are on the map?

To break these apart we could say

that 6 rows of 6 is the same as

5 rows of 6 and 1 row of 6.

So

5 x 6 = _____

Plus 1 x 6 = _____

So

6 x 6 = _____

Break them apart.

7 x 8 8 x 8 6 x 8 7 x 3

6 x 7 9 x 6 5 x 7 4 x 8

8 x 9 3 x 9 8 x 3 7 x 7

Natalie and Kayla are playing chess.

Write a multiplication sentence to find

the total number of squares on the

chessboard.

Jessica, Anna, and Victoria are taking a hiking vacation. They traveled the

distances shown in the table. Who walked the farthest?

HIKERDISTANCE WALKED

JESSICA9 MILES EACH DAY FOR 8 DAYS

ANNA 8 MILES EACH DAY FOR 4 DAYS AND

4 MILES EACH DAY FOR 8 DAYS

VICTORIA 7 MILES EACH DAY FOR 5 DAYS AND

5 MILES EACH DAY FOR 7 DAYS

Mark Twain’s name is taken from

riverboat slang. “Mark twain” means

“Mark two” for 2 fathoms. One fathom

is equal to 6 feet. How many feet

does Mark Twain’s name stand for?

2 - 5

Recalling Multiplication Facts

What are some strategies that can be

used to find products?

Christian visited a summer camp that has 7 tents for the campers to stay in.

Five campers are assigned to each tent. If all of the tents are full, how

many campers are at the camp?

Find the products.

3 x 8 5 x 4 6 x 6 4 x 7

5 x 5 6 x 7 8 x 6 4 x 4

7 x 9 9 x 3 8 x 8 5 x 3

Find the products.

8

x 9

6

x 6

2

x 8

9

x 9

7

x 8

5

x 6

9

x 7

3

x 6

4

x 6

9

x 6

7

x 7

5

x 9

Mia says that she can use the fact

3 x 6 = 18 to find 7 x 6.

Is she correct? Explain her thinking.

Dylan has 9 cases to keep CDs in.

He wants to put 8 CDs in each case.

Draw a bar diagram to find how

many CDs his cases will hold.

Hailey collects Temari balls. Temari

balls originated in China and were

brought to Japan over one thousand

years ago. Hailey arranges the balls

into 3 rows with 8 balls in each row.

What is another way she can arrange

her collection into equal groups?

Arches and Bryce Canyon are two

national parks in Utah. Bryce Canyon

is 35,835 acres in area and Arches

is 76,679 acres in area.

How many acres greater is Arches

National Park?

2 - 6

Draw a Picture to write an equation.

A stegosaurus was 5 times as long

as a velociraptor. If a velociraptor

was 6 feet long, how long was a

stegosaurus?

Samuel has a collection of coins, all of

which are nickels and quarters. He

has 8 nickels and three times as

many quarters.

How many quarters does he have?

How many coins does he have in all?

For the Science Fair, Ben made

a model of a microraptor, one of the

smallest dinosaurs ever discovered.

He made his model 8 inches long.

The actual dinosaur was 3 times the

length of Ben’s model. How long

was a microraptor?

Nathan read that a ceratosaurus was

5 times the length of a microvenator.

A microvenator was 4 feet long.

Use this information to write a problem

you can solve by writing an equation.

Solve.

Sydney’s recipe calls for three times

as many carrots as peas. If Sydney

uses 2 cups of peas, how many

cups of carrots will she use?

Jasmine’s recipe calls for twice as many

tomatoes as peppers. If she uses 4

cups of peppers. How many cups of

tomatoes will she use in all?

Zachary’s dog has a rectangular pen.

The length is two feet longer than the

width. The width is 8 feet. Write an

equation to find the perimeter.

What is the perimeter of the dog pen?

Julia, Morgan, and Destiny swim a relay

race. Morgan swims two more laps

than Julia. Destiny swims twice as many

laps as Julia. If Julia swims 5 laps,

how many laps did they swim all

together?

Rachel is 9 years old. Her mother is

4 times as old as she is.

Use the model to find the age of

Rachel’s mother.

9

Logan, Justin, Gabriel, and Jose are

on a four person relay race team.

They each run an equal part of an 8

mile race. Which equation could you

use to find how far each member runs?

4 + ___ = 8 4 x ___ = 8

4 + 4 + 4 + 4 = ___ 2 x 2 = ___

Topic 2 TEST