&&66
8VHSODFHYDOXHXQGHUVWDQGLQJWRURXQGZKROHQXPEHUVWRWKH
NS 3.1*1%7
Make reasonable
estimates when comparing larger or smaller
QHDUHVWRU
numbers.
UNDERLYING SKILLS AND CONCEPTS:
place value;
compare numbers;
numbers on a number line
Round to the Nearest Ten
When you round, you find the closer ten.
a
K
ey Ide
You can use a number line to round a number to the
nearest ten.
E x am p l E
28
¢
Nikki wants to buy the two goldfish.
Estimate how much she will spend.
Use a number line.
Is 28¢ closer to 20¢ or 30¢?
A – © CSL Associates, Inc. All rights reserved.
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Find 28 on the number line.
28 is closer to 30.
So Nikki will spend about 30¢.
Chapter 16 – Lesson 3
page 187
Name
P RAC T I C E
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
Which ten is nearest?
1
24
20
2
19
20
3
21
20
4
6
10
5
36
40
6
32
30
7
39
40
8
27
30
9
12
10
10
7
10
11
44
40
12
41
40
14
Joey buys a candy bar for
47¢ and gum for 18¢.
13
Brett buys a whistle for 33¢
and a bouncy ball for 49¢.
33 49 is about
30 50
Brett spends about
Math
Reasoning
15
47 18 is about
80
80 ¢.
50 20 Joey spends about
Number Sense
70
70 ¢.
MR 1.2
I am a two-digit number.
I have a 3 in the tens place.
I am not 35. I am closer to 40 than 30.
What numbers could I be?
36, 37, 38, or 39
page 188
Chapter 16 – Lesson 3
A – © CSL Associates, Inc. All rights reserved.
Estimate the sum.
Name
…at home!
P RAC T I C E
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
Which ten is nearest?
1
34
30
2
12
10
3
19
20
4
8
10
5
26
30
6
48
50
7
29
30
8
37
40
9
42
40
10
9
10
11
33
30
12
42
40
14
Mark buys a bouncy ball for
32¢ and a boat for 48¢.
13
John buys a candy bar for
49¢ and gum for 22¢.
32 48 is about
49 22 is about
50 20
John spends about
Math
Reasoning
15
70
70 ¢.
30 50 Mark spends about
Number Sense
80
80 ¢.
MR 1.2
I am a two-digit number.
I have a 2 in the tens place.
I am not 25. I am closer to 30 than 20.
What numbers could I be?
26, 27, 28, or 29
page 126
Home Resource and Homework
Chapter 16 Lesson 3
A – © CSL Associates, Inc. All rights reserved.
Estimate the sum.
MCX94TEG1Ch01_30.v8.4.1 2/19/01 19:22 Page 345
Name
P RAC T I C E
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
Which ten is nearest?
1
24
20
2
19
20
3
21
20
4
6
10
5
36
40
6
32
30
7
39
40
8
27
30
9
12
10
10
7
10
11
44
40
12
41
40
14
Joey buys a candy bar for
47¢ and gum for 18¢.
Estimate the sum.
A – © CSL Associates, Inc. All rights reserved.
13
Brett buys a whistle for 33¢
and a bouncy ball for 49¢.
33 49 is about
30 50
Brett spends about
Math
Reasoning
15
47 18 is about
80
80 ¢.
50 20 Joey spends about
Number Sense
70
70 ¢.
MR 1.2
I am a two-digit number.
I have a 3 in the tens place.
I am not 35. I am closer to 40 than 30.
What numbers could I be?
36, 37, 38, or 39
Chapter 16 – Lesson 3
Student Book Page
page 188
Name
…at home!
P RAC T I C E
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
Which ten is nearest?
1
34
30
2
12
10
3
19
20
4
8
10
5
26
30
6
48
50
7
29
30
8
37
40
9
42
40
10
9
10
11
33
30
12
42
40
14
Mark buys a bouncy ball for
32¢ and a boat for 48¢.
13
John buys a candy bar for
49¢ and gum for 22¢.
32 48 is about
49 22 is about
50 20
John spends about
Math
Reasoning
15
70
70 ¢.
30 50 Mark spends about
Number Sense
80
80 ¢.
MR 1.2
I am a two-digit number.
I have a 2 in the tens place.
I am not 25. I am closer to 30 than 20.
What numbers could I be?
26, 27, 28, or 29
page 126
Home Resource and Homework
Chapter 16 Lesson 3
A – © CSL Associates, Inc. All rights reserved.
Estimate the sum.