Mathematics
Grade 4
15 min
Word problems with extra or missing information
Word problems with extra or missing information
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1
Introduction & Learning Objectives
Learning Objectives
Identify the question being asked in a word problem.
Distinguish between necessary and extra information in a word problem.
Solve multi-step word problems by ignoring irrelevant data.
Identify when a word problem has missing information.
State what specific information is needed to solve a problem with missing data.
Create a plan to solve a word problem using mixed operations.
Have you ever tried to build a LEGO set with extra pieces left over, or with a crucial piece missing? 🤔 Math problems can be just like that!
In this lesson, you'll become a 'Math Detective'! You will learn how to spot extra information that's just there to distract you, and how to figure out when you don't have enough information to solve the puzzle. This...
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Key Concepts & Vocabulary
TermDefinitionExample
Word ProblemA math question that is written as a short story or a real-life scenario.'If a baker makes 120 cookies and sells 95, how many are left?' is a word problem.
Necessary InformationThe specific numbers and facts you absolutely need to answer the question in a word problem.To find the total cost of 3 books at $5 each, the necessary information is '3 books' and '$5 each'.
Extra InformationNumbers or details included in a word problem that you do not need to find the solution. It's also called irrelevant information.In the problem 'Maria, who is 9 years old, bought 4 pencils for $2. How much did one pencil cost?', Maria's age is extra information.
Missing InformationA piece of data that is required to solve the p...
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Core Formulas
The Four-Step Detective Plan
1. Understand -> 2. Plan -> 3. Solve -> 4. Check
Use this four-step process for every word problem. First, read carefully to understand the question and find the data. Second, make a plan, deciding which operations to use and what information is necessary. Third, do the math. Finally, check if your answer makes sense.
The Information Check
Necessary Info - Given Info = ?
Before you solve, think about all the information you need. If the 'Given Info' from the problem doesn't include everything in your 'Necessary Info' list, you have missing information and cannot solve the problem.
4 more steps in this tutorial
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Sign Up Free to ContinueSample Practice Questions
Challenging
You want to find the total number of pages a student read over the weekend. The school is 2 miles from their house. Which set of facts provides the necessary and sufficient information to solve the problem?
A.The student read a 250-page book. They read for 3 hours on Saturday and 2 hours on Sunday.
B.The student read 65 pages on Saturday. The book has 10 chapters.
C.The student read 78 pages on Saturday and 85 pages on Sunday.
D.The student read 4 chapters on Saturday. Each chapter is 20 pages long.
Challenging
A group of 32 students and 4 adults are going on a field trip to a museum that is 50 miles away. The bus costs $400 to rent. Each student ticket costs $8 and each adult ticket costs $12. Which of the following questions CANNOT be answered with the information given?
A.What is the total cost of all the tickets for students and adults?
B.How much does the trip cost per person?
C.What is the total cost for student tickets only?
D.How much more does an adult ticket cost than a student ticket?
Challenging
A family of 4 is buying movie tickets that cost $11 each. They also have a coupon for '$5 off a large popcorn'. A large popcorn costs $9. What is the total cost for the movie tickets?
A.$44
B.$39
C.$48
D.$53
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