Mathematics
Grade 5
15 min
Find two numbers based on sum and difference
Find two numbers based on sum and difference
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1
Introduction & Learning Objectives
Learning Objectives
Identify the sum and difference of two unknown numbers in a word problem.
Apply a systematic approach to find the larger of two numbers given their sum and difference.
Apply a systematic approach to find the smaller of two numbers given their sum and difference.
Solve word problems that require finding two numbers based on their sum and difference.
Verify their answers by checking if the found numbers add up to the given sum and subtract to the given difference.
Explain the steps used to solve problems involving sum and difference.
Have you ever wondered how detectives figure out secret numbers? 🕵️♀️ What if you knew two numbers added up to a certain total, and you also knew how far apart they were?
In this lesson, you'll become a number detective!...
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Key Concepts & Vocabulary
TermDefinitionExample
SumThe result of adding two or more numbers together. It represents the total amount.If you have 5 apples and 3 oranges, their sum is 5 + 3 = 8 fruits.
DifferenceThe result of subtracting one number from another. It tells you how much larger or smaller one number is compared to another.The difference between 10 and 7 is 10 - 7 = 3.
Larger NumberWhen comparing two numbers, the larger number is the one with the greater value.In the pair (15, 8), 15 is the larger number.
Smaller NumberWhen comparing two numbers, the smaller number is the one with the lesser value.In the pair (15, 8), 8 is the smaller number.
TotalAnother word for sum, referring to the whole amount or quantity.The total number of students in two classes is 25 + 28 = 53 students.
Unknown NumbersNumbers th...
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Core Formulas
Finding the Larger Number
$$ \text{Larger Number} = \frac{\text{Sum} + \text{Difference}}{2} $$
To find the larger of the two numbers, first add the given sum and difference together. Then, divide that result by 2. This method works because adding the difference to the sum effectively doubles the larger number.
Finding the Smaller Number
$$ \text{Smaller Number} = \frac{\text{Sum} - \text{Difference}}{2} $$
To find the smaller of the two numbers, first subtract the given difference from the sum. Then, divide that result by 2. This method works because subtracting the difference from the sum effectively doubles the smaller number.
Checking Your Answer
$$ \text{Larger Number} + \text{Smaller Number} = \text{Sum} $$ $$ \text{Larger Number} - \text{Smaller Number} = \text{...
4 more steps in this tutorial
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Challenging
A 90 cm ribbon is cut into two pieces. One piece is 14 cm longer than the other. What is the length of the shorter piece?
A.52 cm
B.76 cm
C.45 cm
D.38 cm
Challenging
The perimeter of a rectangle is 60 meters. The length is 8 meters greater than the width. What is the length of the rectangle?
A.19 meters
B.11 meters
C.30 meters
D.38 meters
Challenging
Set A's numbers have a sum of 100 and a difference of 20. Set B's numbers have a sum of 120 and a difference of 10. What is the difference between the larger number from Set A and the smaller number from Set B?
A.10
B.55
C.5
D.60
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