NS 3.3
UNDERLYING SKILLS AND CONCEPTS:
Solve problems involving multiplication of multi-digit numbers by
two-digit numbers.
multiplication basic facts;
place value
Multiply a 2-Digit by a 1-Digit Number
a
K
ey Ide
You use basic facts and place value when you
multiply by one-digit multipliers.
E x am p l E
1
Find 5 78.
Multiply in each place value.
Then add on regrouped digits.
Step 1:
5 8 40
Multiply the ones by 5.
Step 2:
Multiply the tens by 5.
Record the tens.
Regroup and record
the hundreds.
5 70 350
350 40 390
Hundreds
Tens
3
4
7
8
5
9
0
3
Ones
Record regrouping here.
E x am p l E
2
76 people attended a dog show. Each paid $3. How much did they pay
altogether? Find 3 76.
Step 1:
Step 2:
Step 3:
Write the factors Multiply the ones.
so that the place Record the
values line up.
product as
ones and tens.
Tens
Ones
76
3
1
76
3
8
Step 4:
Multiply the tens.
Record the
Add regrouped tens. hundreds.
Record tens and
hundreds.
21
3 6 18
76
3
28
21
3 70 210
10
220
76
3
228
200
0
200
Altogether they paid $228.
page 86
Chapter 8 – Lesson 1
D – © CSL Associates, Inc. All rights reserved.
So, 5 78 390.
Name
P RAC T I C E
Multiply.
1.
Hundreds
Tens
Ones
6
7
2.
4
Hundreds
Tens
Ones
8
9
4
64
3
6.
Find each product.
3.
72
3
4.
216
7.
19
4
D – © CSL Associates, Inc. All rights reserved.
55
5
5.
594
8.
76
11.
99
6
192
43
2
9.
86
12.
275
87
7
26
8
342
10.
208
13.
609
39
9
351
57
6
88
4
352
14.
67
5
335
Solve each problem.
15. Donna bought 3 jars of spaghetti sauce.
Each jar has 24 ounces of sauce.
How many ounces of spaghetti sauce did she buy?
16. There are 25 computer disks in a box.
How many disks are there in 8 boxes?
Math
Reasoning
72 oz
200 disks
Mystery Number
MR 1.1
17. I am a two-digit number and both of my digits are the same.
When you multiply me by 4, you get a two-digit product.
When you multiply me by 5, you get a three-digit product.
Who am I?
22
Chapter 8 – Lesson 1
page 87
MCX94.HW.CL.G4.FM&Lesson.v211
8/2/04
19:16
Page 58
Name
…at home!
P RAC T I C E
Multiply.
1.
Hundreds
Tens
Ones
3
9
2.
5
Hundreds
Tens
Ones
7
8
6
42
4
6.
Find each product.
63
4
4.
252
7.
18
5
99
4
5.
792
8.
90
11.
88
9
168
39
6
9.
234
12.
396
81
5
44
7
600
10.
308
13.
405
43
3
75
8
66
2
132
14.
129
72
9
648
Solve each problem.
15. Alice bought 6 jars of spaghetti sauce.
Each jar has 24 ounces of sauce.
How many ounces of spaghetti sauce did she buy?
16. There are 25 computer disks in a box.
How many disks are there in 6 boxes?
Math
Reasoning
144 oz
150 disks
Mystery Number
17. I am a two-digit number. Both of my digits are the same.
When you multiply me by 4, you get a two-digit product.
When you multiply me by 5, you get a three-digit product.
Who am I?
page 58
Home Resource and Homework
MR 1.1
22
Chapter 8 Lesson 1
D – © CSL Associates, Inc. All rights reserved.
3.
MCX94TEG4Ch01_32.v8.5.2 2/26/01 19:00 Page 161
Name
P RAC T I C E
Multiply.
1.
Hundreds
Tens
2
2
2.
Ones
6
Tens
3
3
7
8
4
2
Hundreds
6
8
Ones
9
4
3
5
6
Find each product.
3.
72
3
4.
216
7.
19
4
D – © CSL Associates, Inc. All rights reserved.
55
5
5.
594
8.
76
11.
99
6
275
6.
192
43
2
9.
86
12.
64
3
26
8
342
10.
208
87
7
13.
609
39
9
351
57
6
88
4
352
14.
67
5
335
Solve each problem.
15. Donna bought 3 jars of spaghetti sauce.
Each jar has 24 ounces of sauce.
How many ounces of spaghetti sauce did she buy?
16. There are 25 computer disks in a box.
How many disks are there in 8 boxes?
Math
Reasoning
72 oz
200 disks
Mystery Number
MR 1.1
17. I am a two-digit number and both of my digits are the same.
When you multiply me by 4, you get a two-digit product.
When you multiply me by 5, you get a three-digit product.
Who am I?
22
Chapter 8 – Lesson 1
Student Book Page
page 87
Name
…at home!
P RAC T I C E
Multiply.
1.
Hundreds
Tens
1
4
2.
Ones
3
Tens
4
4
9
9
Ones
7
8
5
1
Hundreds
5
6
4
6
8
Find each product.
63
4
4.
252
7.
18
5
99
4
5.
792
8.
90
11.
88
9
39
6
396
81
5
6.
168
9.
234
12.
42
4
44
7
600
10.
308
13.
405
43
3
75
8
66
2
132
14.
129
72
9
648
Solve each problem.
15. Alice bought 6 jars of spaghetti sauce.
Each jar has 24 ounces of sauce.
How many ounces of spaghetti sauce did she buy?
16. There are 25 computer disks in a box.
How many disks are there in 6 boxes?
Math
Reasoning
144 oz
150 disks
Mystery Number
17. I am a two-digit number. Both of my digits are the same.
When you multiply me by 4, you get a two-digit product.
When you multiply me by 5, you get a three-digit product.
Who am I?
page 58
Home Resource and Homework
MR 1.1
22
Chapter 8 Lesson 1
D – © CSL Associates, Inc. All rights reserved.
3.