Percentages are a way of representing a part of a whole as a fraction out of 100. The word ‘percent’ literally means ‘out of one hundred’. So, 72% means 72 out of every 100.
Calculating Percentages
To find a percentage of a number, we can follow these steps:
- Convert the percentage to a decimal: Divide the percentage by 100. For example, 72% becomes 72/100 = 0.72.
- Multiply the decimal by the number: Multiply the decimal you just calculated by the original number. In this case, we multiply 0.72 by £120.
Applying the Steps to Our Problem
- Convert 72% to a decimal: 72 / 100 = 0.72
- Multiply the decimal by £120: 0.72 * £120 = £86.40
Therefore, 72% of £120 is £86.40.
Visualizing Percentages
Imagine a pie cut into 100 equal slices. If you take 72 of those slices, you’re taking 72% of the whole pie. This visual representation helps understand that percentages are simply a way of expressing parts of a whole.
Real-World Applications of Percentages
Percentages are used extensively in everyday life, including:
- Sales and discounts: Stores often offer discounts as percentages, like ‘20% off’.
- Taxes: Sales tax is often calculated as a percentage of the purchase price.
- Interest rates: Banks use percentages to calculate interest on savings accounts and loans.
- Statistics and data analysis: Percentages are used to represent proportions and trends in data.
Example: Calculating a Discount
Let’s say you want to buy a shirt that costs £30, and it’s on sale for 25% off. To calculate the discount, we follow the same steps:
- Convert 25% to a decimal: 25 / 100 = 0.25
- Multiply the decimal by the original price: 0.25 * £30 = £7.50
Therefore, the discount is £7.50. To find the final price, subtract the discount from the original price: £30 – £7.50 = £22.50. You would pay £22.50 for the shirt after the discount.
Key Takeaways
- Percentages are a powerful tool for representing parts of a whole.
- Converting percentages to decimals makes calculations easier.
- Percentages are widely used in various real-world scenarios.