Percentage Increase and Decrease
Enroll to start learning
Youβve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Introduction to Percentage Increase
π Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Today, we are going to learn about percentage increase. To start, can anyone tell me what percentage means?
Isn't it just a way to express a number as a fraction of 100?
Exactly! Now, when we talk about percentage increase, we are looking at how much something has grown. The formula is: (New Value - Original Value) / Original Value x 100. Can anyone give me an example where we might use this?
Like when prices go up during sales?
Good example! Letβs say a shirt originally costs $20, and now it's $25. How would you calculate the percentage increase?
I think it would be (25 - 20) / 20 x 100, which equals 25%!
Well done! So, the price increased by 25%. Remember, to find the percentage increase, we subtract the original from the new value, divide by the original, and multiply by 100. Let's summarize this point!
Introduction to Percentage Decrease
π Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Now that we understand percentage increase, let's discuss percentage decrease. Can anyone describe what this might mean in context?
It probably relates to prices or values going down, like sales discounts.
Absolutely! The formula for percentage decrease is similar: (Original Value - New Value) / Original Value x 100. What happens if a product went from $50 to $30?
That would be (50 - 30) / 50 x 100; I think itβs 40%.
Excellent! So that means there was a 40% decrease. Always remember to use the original value in your calculations. Letβs wrap up today's discussion on these terms.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
Percentage increase and decrease are fundamental concepts that help in evaluating changes in quantities and understanding real-world applications, such as discounts and profit calculations. This section delves into formulas and examples to illustrate how these calculations are performed.
Detailed
Percentage Increase and Decrease
Understanding Percentages
Percentage increase and decrease are critical for making sense of changes in values within various contexts, especially in financial mathematics, commerce, and data analysis.
Percentage Increase
- Definition: The percentage increase quantifies how much a value has grown relative to its original amount.
- Formula:
\
Percentage Increase = ((New Value - Original Value) / Original Value) x 100 \
Percentage Decrease
- Definition: The percentage decrease shows how much a value has declined compared to its initial value.
- Formula:
\
Percentage Decrease = ((Original Value - New Value) / Original Value) x 100 \
Significance
Understanding these concepts enables individuals to make informed decisions regarding budgeting, investments, pricing strategies, and interpreting data trends accurately. Through the lens of quantitative literacy, learners can apply these principles to real-world scenarios effectively.
Key Concepts
-
Percentage Increase: A growth measure of a number relative to its original amount.
-
Percentage Decrease: A decline measure showing how much a number diminishes from its initial value.
Examples & Applications
If a car's price rises from $22,000 to $24,200, the percentage increase can be calculated as ((24,200 - 22,000) / 22,000) * 100 = 10%.
A smartphone originally costs $800 and is discounted to $640. The percentage decrease would be ((800 - 640) / 800) * 100 = 20%.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
For increase, it's a gain, from the original we do refrain.
Stories
Once there was a store where prices could increase and decrease, with each sale telling a tale of growth or loss that made shoppers prevail!
Memory Tools
I = O + N (Increase equals Original plus New Value).
Acronyms
PID
Percentage Increase Denoted by Increase.
Flash Cards
Glossary
- Percentage Increase
A measure of how much a quantity has grown compared to its original size, expressed in a percentage.
- Percentage Decrease
A measure of how much a quantity has shrunk relative to its original size, also expressed as a percentage.
Reference links
Supplementary resources to enhance your learning experience.