Page 63 - Basic College Mathematics with Early Integers

40 C HAPTE R 1 I THE WHOLE NUMBERS

PRACTICE 1 Example 1 Round 568 to the nearest ten.
Round to the nearest ten.
Solution: 568 The digit to the right of the tens place is the ones place,
a. 57
which is circled.
b. 641 tens place
c. 325
568 Since the circled digit is 5 or greater, add 1 to the 6 in
the tens place and replace the digit to the right by 0.
Add 1. Replace
with 0.
We find that 568 rounded to the nearest ten is 570.

Work Practice 1

PRACTICE 2 Example 2 Round 278,362 to the nearest thousand.
Round to the nearest thousand.
Solution: Thousands place
a. 72,304
3 is less than 5.
b. 9222
278, 3 62
c. 671,800
Do not add 1. Replace with zeros.

The number 278,362 rounded to the nearest thousand is 278,000.
Work Practice 2

PRACTICE 3 Example 3 Round 248,982 to the nearest hundred.

Round to the nearest hundred.
Solution: Hundreds place
a. 3474
8 is greater than or equal to 5.
b. 76,243
248,9 8 2
c. 978,965
Add 1. 9+1=10, so replace the digit 9 by 0 and carry 1 to the
place value to the left.
8+1 0
2 4 8, 9 82

Add 1. Replace with zeros.
The number 248,982 rounded to the nearest hundred is 249,000.

Work Practice 3

Concept Check Round each of the following numbers to the nearest
hundred. Explain your reasoning.
a. 59 b. 29
Answers
1. a. 60 b. 640 c. 330
2. a. 72,000 b. 9000 c. 672,000 Objective Estimating Sums and Differences
3. a. 3500 b. 76,200 c. 979,000 Copyright 2012 Pearson Education, Inc.
By rounding addends, minuends, and subtrahends, we can estimate sums and differ-
ences. An estimated sum or difference is appropriate when the exact number is not
Concept Check Answers necessary. Also, an estimated sum or difference can help us determine if we made a
a. 100 b. 0