NS 3.2*2$
Demonstrate
an understanding of, and ability to use, standard
&&66
0XOWLSO\RUGLYLGHWRVROYHZRUGSUREOHPVLQYROYLQJPXOWLSOLFDWLYH
FRPSDULVRQHJE\XVLQJGUDZLQJVDQGHTXDWLRQVZLWKDV\PEROIRUWKHXQNQRZQ
algorithms for multiplying a multi-digit number by a two-digit
QXPEHUWRUHSUHVHQWWKHSUREOHPGLVWLQJXLVKLQJPXOWLSOLFDWLYHFRPSDULVRQIURPDGGLWLYH
number and for dividing a multi-digit number by a one-digit
FRPSDULVRQnumber; use relationships between them to simplify
UNDERLYING SKILLS AND CONCEPTS:
meaning of multiplication; meaning of
division; multiplication basic facts;
division basic facts
computations and to check results.
Choose the Operation (Multiply or Divide)
a
K
ey Ide
You can use multiplication or
division to solve some kinds of
problems.
You can use the inverse operation to check
your answer.
E x am p l E
!
Mrs. Clark put the desks in her room
into groups of 4.
"
There are 8 groups of desks.
What is the total number of desks in her room?
What do you need to find out?
What information can you use to answer the question?
The desks are in groups of 4.
There are 8 groups of desks.
How can you solve the problem?
Since you want to find the total number,
you multiply.
8 ! 4 " 32
There are a total of 32 desks.
How can you check your answer?
You can divide the total number of desks by the
number of groups of desks.
It's a !
!
32 # 8 " 4
The answer checks.
page 78
Chapter 7 – Lesson 3
D – © CSL Associates, Inc. All rights reserved.
The total number of desks in her room.
Name
P RAC T I C E
Which operation would you use to answer the question?
1. Dara bought 3 pens for 29¢ each.
How much did Dara pay for the pens?
multiplication
2. Enrique ran 4 times around the track.
Altogether he ran 1.6 miles.
How long is the track?
division
3. How many minutes are there in five hours?
multiplication
Choose the operation. Write an equation and solve.
4. Ginger picks up balls at the tennis club.
On Saturday she picked up 27 balls.
She puts 3 balls in each can.
How many cans did she fill?
27 3 9 cans
D – © CSL Associates, Inc. All rights reserved.
5. There are 10 boxes of crayons in the room.
Each box holds 8 crayons.
What is the total number of crayons in the room?10 8 80 crayons
6. Mr. Adams bought 7 packages of floppy disks
for the computer lab. Each package had 12 disks.
How many disks did he buy?
7. Joy needed 54 thank you cards.
She found them in packages of 6.
How many packages should she buy?
Math
Reasoning
12 7 84 disks
54 6 9 packages
Number Sense
MR 3.1
8. Lynn had 24 photos. She put 6 photos on each page of her album.
She said she would need to use 144 pages.
Is this reasonable? Explain.
No; Possible answer: Since she is putting more than one
photo on a page, she needs fewer pages than photos. She
should have divided instead of multiplying.
Chapter 7 – Lesson 3
page 79
MCX94.HW.CL.G4.FM&Lesson.v211
8/2/04
19:16
Page 54
Name
…at home!
P RAC T I C E
Which operation would you use to answer the question?
1. Melanie bought 5 markers for 79¢ each.
How much did Melanie pay for the markers?
multiplication
2. Craig ran 6 times around the track.
Altogether he ran 2.4 miles.
How long is the track?
3. How many minutes are there in seven hours?
division
multiplication
Choose the operation. Write an equation and solve.
4. Becky picks peaches at an orchard.
On Saturday she picked 48 peaches.
She puts 6 peaches in each carton.
How many cartons did she fill?
division;
48 6 8 cartons
6. Mr. Rinaldi bought 6 cartons of eggs.
Each carton had 18 eggs.
How many eggs did he buy?
multiplication;
18 6 108 eggs
7. Dawn needed 42 note cards.
She found them in packages of 6.
How many packages should she buy?
division;
42 6 7 packages
Math
Reasoning
Number Sense
MR 3.1
8. Morgan had 36 soccer cards. She put 6 soccer cards on each page of her
album. She said she would need to use 216 pages.
Is this reasonable? Explain.
No; Possible answer: Since she is putting more than one
card on a page, she needs fewer pages than cards. She
should have divided instead of multiplying.
page 54
Home Resource and Homework
Chapter 7 Lesson 3
D – © CSL Associates, Inc. All rights reserved.
5. There are 12 boxes of markers in the room.
multiplication;
Each box holds 8 markers.
What is the total number of markers in the room?112 8 96 markers
MCX94TEG4Ch01_32.v8.5.2 2/26/01 18:59 Page 147
Name
P RAC T I C E
Which operation would you use to answer the question?
1. Dara bought 3 pens for 29¢ each.
How much did Dara pay for the pens?
multiplication
2. Enrique ran 4 times around the track.
Altogether he ran 1.6 miles.
How long is the track?
division
3. How many minutes are there in five hours?
multiplication
Choose the operation. Write an equation and solve.
4. Ginger picks up balls at the tennis club.
On Saturday she picked up 27 balls.
She puts 3 balls in each can.
How many cans did she fill?
27 3 9 cans
D – © CSL Associates, Inc. All rights reserved.
5. There are 10 boxes of crayons in the room.
Each box holds 8 crayons.
What is the total number of crayons in the room?10 8 80 crayons
6. Mr. Adams bought 7 packages of floppy disks
for the computer lab. Each package had 12 disks.
How many disks did he buy?
7. Joy needed 54 thank you cards.
She found them in packages of 6.
How many packages should she buy?
Math
Reasoning
12 7 84 disks
54 6 9 packages
Number Sense
MR 3.1
8. Lynn had 24 photos. She put 6 photos on each page of her album.
She said she would need to use 144 pages.
Is this reasonable? Explain.
No; possible answer: Since she is putting more than one
photo on a page, she needs fewer pages than photos. She
should have divided instead of multiplying.
Chapter 7 – Lesson 3
Student Book Page
page 79
Name
…at home!
P RAC T I C E
Which operation would you use to answer the question?
1. Melanie bought 5 markers for 79¢ each.
How much did Melanie pay for the markers?
multiplication
2. Craig ran 6 times around the track.
Altogether he ran 2.4 miles.
How long is the track?
3. How many minutes are there in seven hours?
division
multiplication
Choose the operation. Write an equation and solve.
4. Becky picks peaches at an orchard.
On Saturday she picked 48 peaches.
She puts 6 peaches in each carton.
How many cartons did she fill?
division;
48 6 8 cartons
6. Mr. Rinaldi bought 6 cartons of eggs.
Each carton had 18 eggs.
How many eggs did he buy?
multiplication;
18 6 108 eggs
7. Dawn needed 42 note cards.
She found them in packages of 6.
How many packages should she buy?
division;
42 6 7 packages
Math
Reasoning
Number Sense
MR 3.1
8. Morgan had 36 soccer cards. She put 6 soccer cards on each page of her
album. She said she would need to use 216 pages.
Is this reasonable? Explain.
No; Possible answer: Since she is putting more than one
card on a page, she needs fewer pages than cards. She
should have divided instead of multiplying.
page 54
Home Resource and Homework
Chapter 7 Lesson 3
D – © CSL Associates, Inc. All rights reserved.
5. There are 12 boxes of markers in the room.
multiplication;
Each box holds 8 markers.
What is the total number of markers in the room?112 8 96 markers