Reverse Percentage Calculations
This page provides a comprehensive guide on how to perform reverse percentage calculations in various scenarios, including both increases and decreases. The information is crucial for students learning to find the original number of a percentage increase or decrease.
Reverse Percentage for Increases
To calculate the original value from a percentage increase, follow these steps:
- Convert the percentage to a decimal
- Add 1 to the decimal
- Divide the new amount by the result from step 2
Highlight: This method is particularly useful when you need to find the original price after a percentage increase.
Reverse Percentage for Decreases
The process for decreases is slightly different:
- Convert the percentage to a decimal
- Subtract the decimal from 1.00
- Divide the new amount by the result from step 2
Vocabulary: Reverse percentage formula - The mathematical expression used to find the original value before a percentage change was applied.
Practical Example
The guide provides an example to illustrate the reverse percentage increase calculation:
Patrick invested money in a bank account that earns 4% interest annually. After one year, the account balance is £291.20. To find Patrick's original investment:
- Convert 4% to 0.04
- Add 1: 1.00 + 0.04 = 1.04
- Divide the new amount by 1.04: £291.20 ÷ 1.04 = £280
Example: This demonstrates how to find the original amount after a percentage increase, which is a common application in financial calculations.
Highlight: Understanding these steps to find original price after percentage increase is crucial for solving various real-world problems, from finance to data analysis.
The page emphasizes the importance of these calculations, making it a valuable resource for those learning to work with percentages and their applications in practical scenarios.
