Problem 15 Estimate by rounding as directed... [FREE SOLUTION] (2024)

Get started for free

Log In Start studying!

Get started for free Log out

Chapter 4: Problem 15

Estimate by rounding as directed. $$ \begin{aligned} &198.67432-24.5007\\\ &\text { nearest ten } \end{aligned} $$

Short Answer

Expert verified

The estimated result is 180.

Step by step solution


Understand the problem

The problem requires estimating the result of subtracting two numbers by rounding them to the nearest ten. The given numbers are 198.67432 and 24.5007.


Round the first number to the nearest ten

Round 198.67432 to the nearest ten. The digit in the tens place of 198.67432 is 9, and the next digit (hundreds place) is 1. Since the digit in the tens place is closer to 20, round up. So, 198.67432 rounds to 200.


Round the second number to the nearest ten

Round 24.5007 to the nearest ten. The digit in the tens place of 24.5007 is 4, and the next digit is 2. Since 4 is closer to 0 than to 10, round down. Hence, 24.5007 rounds to 20.


Subtract the rounded numbers

Subtract the rounded numbers from step 2 and 3: 200 - 20.


Calculate the result

Perform the subtraction: 200 - 20 = 180.

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

nearest ten

When we are asked to round to the nearest ten, we look at the tens and units place of a number. For instance:
If we have 198.67432, we observe the digit in the tens place, which is '9', and the digit right before it (units place), which is '1'.
If the units digit is 5 or more, we round up. If it's less than 5, we round down.
So, for 198.67432, even though the 1 in the units place might normally cause us to round down, there's a trick here!
Ultimately, we rounded 198.67432 to 200 because the digit in the tens place is 9, which rounds to the next nearest hundred. For numbers like 24.5007, the digit in the tens place is '4', and the units digit is '2'.
Since 2 is less than 5, we round down, resulting in 20.
Applying these rules helps us to simplify numbers, making calculations easier.


Estimation is a fundamental concept in mathematics that helps in quickly finding an answer without needing an exact figure.
Here’s why it’s useful:

  • Simplifies complex calculations
  • Saves time
  • Offers a quick check on the accuracy of detailed calculations

When estimating, it’s important to round numbers to the nearest ten, hundred, or other convenient value.
This gives a general sense of the size of the numbers and the result of the operation.
For example, in our exercise, by rounding 198.67432 to 200 and 24.5007 to 20, subtraction becomes straightforward.
Learn to estimate well, and you’ll find yourself more comfortable with numbers in daily life and exams.


Subtraction is a basic arithmetic operation that represents the operation of removing objects from a collection.
In our task, after rounding the numbers, we needed to subtract 20 from 200. Here’s how subtraction works step-by-step:
When subtracting smaller numbers from larger numbers, you essentially reduce the quantity.
For instance:

  • Start with the larger number: 200.
  • Subtract the smaller number: 200 - 20.
  • The result is 180.

Subtracting rounded numbers simplifies the process and provides an approximation close to the exact result.
It’s much easier to deal with especially when working with large or very detailed numbers.
Understanding subtraction and practicing it with rounding and estimation will improve accuracy and speed in solving mathematical problems.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Problem 15 Estimate by rounding as directed... [FREE SOLUTION] (3)

Most popular questions from this chapter

What is the cost of 12.6 gal of gasoline at \(\$ 2.89\) per gallon? Round theanswer to the nearest cent.Add. $$ 4 \frac{1}{3}+2 \frac{1}{2} $$Simplify. $$ 200+40 \div 4 $$Add. $$ \begin{array}{r} 4203.28 \\ +\quad 3.39 \\ \hline \end{array} $$Add. $$ \begin{array}{r} 9.104 \\ +123.456 \\ \hline \end{array} $$
See all solutions

Recommended explanations on Math Textbooks

Decision Maths

Read Explanation


Read Explanation

Applied Mathematics

Read Explanation


Read Explanation

Theoretical and Mathematical Physics

Read Explanation

Pure Maths

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept

Privacy & Cookies Policy

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.


Always Enabled

Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.


Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.

Problem 15 Estimate by rounding as directed... [FREE SOLUTION] (2024)
Top Articles
Latest Posts
Article information

Author: Jonah Leffler

Last Updated:

Views: 5475

Rating: 4.4 / 5 (45 voted)

Reviews: 92% of readers found this page helpful

Author information

Name: Jonah Leffler

Birthday: 1997-10-27

Address: 8987 Kieth Ports, Luettgenland, CT 54657-9808

Phone: +2611128251586

Job: Mining Supervisor

Hobby: Worldbuilding, Electronics, Amateur radio, Skiing, Cycling, Jogging, Taxidermy

Introduction: My name is Jonah Leffler, I am a determined, faithful, outstanding, inexpensive, cheerful, determined, smiling person who loves writing and wants to share my knowledge and understanding with you.