## Envision Math 4th Grade Textbook Answer Key Topic 2.1 Understanding Rounding

Review What You Know

Vocabulary

Choose the best term from the box. Question 1.
In order to subtract 141 from 530, you need to __.

Question 2.

Question 3.
When you subtract two numbers, the answer is the __.

Question 4.
When you add numbers together, you find the __.

Find the sum.

Question 5.
4 + 6

Question 6.
7 + 5

Question 7.
9 + 8

Question 8.
14 + 5

Question 9.
3 + 7

Question 10.
37 + 7

Question 11.
9 + 6

Question 12.
6 + 5

Question 13.
15 + 7

Question 14.
3 + 8

Question 15.
14 + 6

Question 16.
25 + 5

Subtraction Facts

Find the difference.

Question 17.
27 – 3

Question 18.
6 – 4

Question 19.
15 – 8

Question 20.
11 – 8

Question 21.
6 – 2

Question 22.
17 – 8

Question 23.
16 – 4

Question 24.
20 – 5

Question 25.
11 – 6

Question 26.
14 – 6

Question 27.
15 – 10

Question 28.
13 – 7

Question 29.
Writing to Explain Why does 843 round to 840 rather than to 850?

Understanding Rounding

Why do you round numbers?
Rounding replaces one number with another number that tells about how many or how much.

The Golden Gate Bridge’s towers reach a height of 746 feet. What is 746 rounded to the nearest ten? to the nearest hundred?

Guided Practice*

Do you know HOW?

In 1 through 4, use a number line to round each number to the place of the underlined digit.

Question 1.
2, 286

Question 2.
5,747

Question 3.
153

Question 4.
8,639

Do You Understand?

Question 5.
In the number lines above, why are the halfway point numbers different?

Question 6.
In New York, the Verrazano-Narrows Bridge’s towers reach a height of 693 feet. What is 693 rounded to
the nearest ten?

Independent Practice

Leveled Practice For 7 and 8, use the number line to round each number to the place of the underlined digit.

Question 7.
656 Question 8.
9,129 For 9 through 23, use a number line to round each number to the place of the underlined digit.

Question 9.
7,241

Question 10.
3,414

Question 11.
2,639

Question 12.
561

Question 13.
295

Question 14.
206

Question 15.
6,028

Question 16.
873

Question 17.
123

Question 18.
1,999

Question 19.
4,183

Question 20.
647

Question 21.
3,809

Question 22.
792

Question 23.
8,299

Use a number line to round 746 to the nearest ten.
Compare 746 to the halfway point, which is 745. 746 is to the right of the halfway point, so round to 750.

Use a number line to round 746 to the nearest hundred.
Compare 746 to the halfway point, which is 750. 746 is to the left of the halfway point, so round to 700.

Problem Solving

For 24 and 25, use the table at the right. Question 24.
Write the number of cities in each state in expanded form. Then order the numbers from greatest to least.

Question 25.
Round each number in the table to the nearest ten. Then order the rounded numbers from least to greatest.

Question 26.
Number Sense Write four numbers that round to 500 when rounded to the nearest hundred.

Question 27.
The attendance at a football game at California Memorial Stadium was 54,387. What is this number rounded to the nearest hundred?

Question 28.
At a football game, a scoreboard showed the attendance at the game to be 35,396. Which choice is this number rounded to the nearest ten?
A. 35,000
B. 35,300
C. 35,390
D. 35,400  