101 LearnersLast updated on June 4th, 2025
Percent Difference
Percent difference is an essential concept in math that helps students compare the relative differences between two numbers. The term percent is the portion of 100 representing a ratio or fraction of a whole (100). It helps students self-evaluate their academic performance based on the percentage difference. Let's find out more about the percentage difference.
What is Percent Difference in Math?
We can calculate the percentage difference by dividing the difference of two values by their average and then multiplying the result by 100. It is an important concept that can be used in mark calculations and other daily life situations where percent difference is involved. The formula that we commonly apply to measure the percent difference:
Here, A and B are the two values we compare to calculate the percent difference.
How to Calculate Percentage Difference?
To calculate the difference between the percentage of the two values, we need to use the following step-by-step process:
Step 1:Identify the two values
Step 2:Subtract the given values to find their difference, for instance: (a - b).
Step 3:To find the average of two given values, add the numbers and divide by 2, i.e. (a + b)/2
Step 4:Next, we divide the difference by the average.
Step 5: The calculated fraction can be multiplied by 100 to simplify the answer.
Let’s take an example:
Percentage of Sam: 75%
Percentage of Ben: 62%
To find the percent difference, we apply the values into the formula:
Tips and Tricks for Calculating the Percentage Difference
The percentage difference helps children determine the difference in academic performance based on the percentage scored. We will now discuss a few tips and tricks that make it easier to calculate the percentage difference.
- To avoid the calculation error, make sure to calculate the absolute difference between the two different values.
- Finding the average is simply adding two numbers and dividing the result by 2.
- Always check for any errors when you are rounding the decimal values to ensure accuracy.
- Use a calculator when determining the percentage difference of larger values.
- Applying the concept in real-life situations helps you calculate it quickly.
Common Mistakes and How to Avoid Them in Percentage Difference
Students may make some mistakes when calculating the percentage difference. To master the concept, they need to identify the errors and learn ways to avoid them. Let’s look at some:
Mistake 1
Not Using the Absolute Values
Children often don’t use the absolute value while finding the absolute difference. The absolute difference is the positive difference between two values regardless of the order of the numbers.
For example (incorrect): If A = 30 and B = 60, the absolute difference is -30.
Ensure that you calculate the difference by taking the absolute values to avoid errors that lead to negative values. The correct absolute difference of the above-mentioned example is 30.
Real-World Applications of Percent Difference
The percent difference has numerous real-life applications. Understanding these helps children apply the concept in real situations. Let’s explore a few:
- Percent difference helps students in comparing experimental results not only in math but also in other subjects like physics, biology and chemistry.
- They apply the percent difference formula to calculate their academic progress.
- It enables students to compare their performance in sports, such as in comparing the speed or score differences.
- They also learn how it applies to the medical field, such as comparing blood pressure results.
- Moreover, it helps them to compare the price differences when shopping for clothes of their choice.
Solved Examples of Percent Difference
Problem 1
If A= 80 and B = 100, calculate the percent difference between the given values.
22.22% is the percent difference between the values
A= 80 and B = 100
Explanation
To solve, we will use the formula:
Substituting the given values:
= (20/ 90) × 100
= 0.2222 × 100 = 22.22%
Therefore, the percent difference of the given values is 22.22%.
Problem 2
Lisa brought a bag that costs $300 which was originally priced at $550. Determine the percent difference in price.
The percent difference is 58.82%.
Explanation
Assume,
(original price) $550 = A
(New price) $300 = B
Determining the absolute difference in price:
550 - 300 = 250
Now we find the average of the two prices:
(550 + 300)/2 = 425
As a final step, we calculate the percent difference:
(250/425) × 100 = 58.82%
Therefore, the percent difference is 58.82%.
Problem 3
Cathy scored 70% in her first-semester examination and 85% in the second semester. What is the percent difference in her score?
The percent difference in Cathy’s score is 19.35%.
Explanation
Assume,
First semester 70% = A
Second semester 85% = B
The absolute difference in scores:
85- 70 = 15
Average of the two scores:
(85 + 70)/2 = 77.5
Percentage difference:
(15/ 77.5) × 100 = 19.35%
Therefore, we get the percent difference in Cathy’s score as 19.35%.
Problem 4
Merlin used to have an average screen time 6 hours a day, which got reduced to 3 hours due to her exams. Calculate the percent difference.
The percent difference is 66.67 %.
Explanation
Initial screen time, A = 6 hours
Reduced screen time, B = 3 hours
The absolute difference:
6-3 = 3
The average of the two screen time:
(6 + 3)/2 = 4.5
We now calculate the percent difference:
(3/4.5) × 100 = 66.67 %
Therefore, the percent difference is 66.67 %.
Problem 5
Calculate the percent difference if A= 50 and B = 90
The percent difference is 57.14%
Explanation
Here, we use the formula:
Substituting the values into the formula: 90- 50 = 40
The average of A and B:
(50 +90)/2 = 70
We now calculate the percentage difference:
(40/70) × 100 = 57.14%
Therefore, the percent difference is 57.14%
FAQs on Percent Difference
1.What is the percent difference?
2.Give the formula for the percent difference.
3.Find the percent difference between 10 and 8 using the formula.
4.Why do we calculate the percent difference using the absolute value?
5.Are the percentage difference formula and the percentage change formula the same?
6.Is it possible for the percentage difference to be negative?
7.What does a 0 % percent difference suggest?
8.What is an absolute difference?
9.Is it possible to calculate the percent difference for more than two numbers?
10.Give one real-life application of percent difference.
11.How can children in Thailand use numbers in everyday life to understand Percent Difference?
12.What are some fun ways kids in Thailand can practice Percent Difference with numbers?
13.What role do numbers and Percent Difference play in helping children in Thailand develop problem-solving skills?
14.How can families in Thailand create number-rich environments to improve Percent Difference skills?
Dr. Sarita Ghanshyam Tiwari
About the Author
Dr. Sarita Tiwari is a passionate educator specializing in Commercial Math, Vedic Math, and Abacus, with a mission to make numbers magical for young learners. With 8+ years of teaching experience and a Ph.D. in Business Economics, she blends academic rigo
Fun Fact
: She believes math is like music—once you understand the rhythm, everything just flows!
