Copyright

Solving Multi-Step Word Problems with the 4 Operations: Lesson for Kids

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Points, Lines & Angles in Geometry

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:04 Data & Variables
  • 0:42 Collecting Evidence
  • 2:42 Problems Involving…
  • 3:34 Problems With Time
  • 4:05 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Timeline
Autoplay
Autoplay
Speed Speed Audio mode
Lesson Transcript
Instructor: Nick Rogers
Word problems are like puzzles. You need to identify the things that you know and determine how to find the answer using those facts. The things that we do know are called data, and the things that we don't are called variables.

Data & Variables

You can think of word problems as mysteries that need to be solved. First, you must collect all of the 'clues,' or the evidence. Write down everything that you know, and then decide which parts are relevant to the case. As mathematicians, we call this evidence data, while the part that we don't know is called a variable because it's allowed to vary.

Just like Sherlock Holmes, you will deduce the answer from the things that you do know. A good detective is clear about what assumptions they have to make, and a good mathematician does the same thing. Be clear about what you want to find and how you can use the resources that you have to find it.

Collecting Evidence

Let's start with an example problem. Sarah is reading her math textbook. The first three chapters had 20 pages. The last four have 30 pages each. In total, the book contains 400 pages. How many pages are in the middle chapters?

You should start this problem by writing down what you know. The first three chapters have 20 pages each. Therefore, they contain 20 + 20 + 20 = 60 pages. The last four chapters have 30 pages each. They have 30 + 30 + 30 + 30 = 120 pages. The middle chapters contain the rest. This is the data, or the things that we know.

Next, you should identify what we want to know. The question asks us very directly: how many pages are in the middle chapters? Let's give a name to the number that we're looking for. We'll call it x, so the pages in the middle = x. We can write this all down as an equation:

Pages in First Chapters + Pages in Middle + Pages in Final Chapters = 400

Now, let's replace these words with the numbers we know:

60 + x + 120 = 400.

At this point, we're ready to find x. Apply some mathematical techniques in order to do that. Subtract 60 and 120 from each side, then cancel some things out:

60 + x + 120 - 60 -120 = 400 - 60 - 120

Therefore, x = 220

After finishing your solution, you should make sure that this answer makes sense. If the middle chapters have 220 pages, and the beginning chapters have 60, and the final chapters have 120, then do we have the right amount of pages? Yes, since 60 + 120 + 220 = 400.

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account
Support