# How to Find a Percentage: A Step-by-Step Guide with Examples

## I. Introduction

Have you ever wondered how to find a percentage? A percentage is a way to express a fraction or a proportion as a fraction of 100. Understanding percentages is important in many areas of life, such as finance, health, and education. In this article, we’ll explore the basics of calculating percentages, different scenarios where percentages come in handy, practice problems with solutions, tips and tricks for finding percentages, and resources to help you improve your percentage skills.

### A. Explanation of What a Percentage Is

A percentage (%), also known as a percent, is a way to express a fraction or a proportion as a fraction of 100. For example, if we say that 50% of the students in a classroom are girls, we mean that 50 out of every 100 students are girls. Percentages are commonly used to describe changes in quantities, as well as to compare quantities.

### B. Importance of Knowing How to Find a Percentage

Understanding how to find a percentage is important in many areas of life, ranging from calculating discounts and taxes to understanding financial investments and medical test results. By knowing how to calculate percentages, you can make informed decisions in various situations.

### C. Examples of Real-World Scenarios Where Percentages Are Used

Here are a few examples of real-world scenarios where percentages are commonly used:

• Finance: calculating interest rates, investments, and discounts
• Health: interpreting blood tests, calculating BMI, and tracking weight loss
• Education: calculating test scores and grades
• Sports: calculating batting averages, field goal percentages, and game statistics
• Marketing: measuring response rates and conversion rates

## II. Calculation of Percentages

Now that we understand what a percentage is and why it’s important to know how to find one, let’s dive into the basics of calculating percentages.

### A. Basic Formulas for Finding Percentages

There are three basic formulas for finding percentages:

• Part / Whole * 100%: This formula can be used when you have two quantities and you want to find the percentage that one quantity represents of the other. For example, if you have 40 boys and 60 girls in a classroom, and you want to find the percentage of boys, you can use the formula: 40 / (40 + 60) * 100% = 40%.
• Change / Original * 100%: This formula can be used when you want to find the percentage increase or decrease between two quantities. For example, if a company’s sales increased from \$100,000 to \$120,000 in a year, you can use the formula: (120,000 – 100,000) / 100,000 * 100% = 20% increase.
• Percentage / 100 * Whole: This formula can be used when you want to find what percentage one quantity represents of another quantity. For example, if you have a \$50 discount on a \$200 product, you can use the formula: 50 / 100 * 200 = \$100.

### B. Step-By-Step Guide for Calculating Percentages

Here’s a step-by-step guide for how to calculate a percentage:

1. Identify the two quantities that you need to work with. For example, you may need to find the percentage of boys in a classroom, or the percentage increase in sales for a company.
2. Determine which formula you need to use. The formula will depend on the type of problem you’re trying to solve.
3. Plug in the numbers from your problem into the appropriate formula.
4. Multiply, divide, and simplify the fractions and decimals until you get your final answer.

### C. Examples to Illustrate the Calculation Process

Let’s take a look at a few examples to illustrate the calculation process:

1. Example 1: If there are 10 red balls and 20 blue balls in a bag, what percentage of the balls are red?
1. Identify the two quantities: red balls and total balls.
2. Determine the formula: part / whole * 100%
3. Plug in the numbers: 10 / (10 + 20) * 100%
4. Simplify the fraction: 10 / 30 * 100%
6. Express the answer as a percentage: 33.33%.
2. Example 2: If a car that originally cost \$20,000 increases in value to \$24,000, what is the percentage increase in value?
1. Identify the two quantities: original value and new value.
2. Determine the formula: (new – old) / old * 100%
3. Plug in the numbers: (24,000 – 20,000) / 20,000 * 100%
5. Express the answer as a percentage: 20%.

## III. Different Scenarios Where Percentages Come in Handy

Percentages are used in many different scenarios in everyday life. Here are a few examples:

### A. Discounts and Sales

Percentages are commonly used in sales and marketing to describe discounts. For example, a store may offer a 20% discount on a product to attract customers. By knowing how to calculate the discount, you can determine the sale price of the product and decide whether the deal is worth it.

### B. Taxes and Tips

Percentages are also used to calculate taxes and tips. For example, in the United States, sales tax is usually around 7-8% of the purchase price. By knowing the tax rate, you can calculate the total cost of a purchase. Tipping at restaurants is another common scenario where percentages are used. A typical tip amount is around 15-20% of the total bill.

### C. Population Growth and Decline

Percentages are also used to describe population growth and decline. For example, if a city’s population increases from 100,000 to 110,000 in a year, the percentage increase in population is 10%. By understanding population growth rates, governments and planners can make decisions about how to allocate resources and plan for the future.

### D. Interest Rates and Investments

Percentages are also used in finance to describe interest rates and investment returns. For example, if you invest \$100 in a savings account with a 5% annual interest rate, you’ll earn \$5 in interest per year. By knowing how to calculate interest rates and investment returns, you can make informed financial decisions and plan for your future.

## IV. Practice Problems

Practice makes perfect when it comes to calculating percentages! Here are some real-world practice problems to help you hone your skills:

1. If a shirt costs \$20 and is on sale for 25% off, what is the sale price?
2. If a city’s population decreases from 500,000 to 450,000 in a year, what is the percentage decrease?
3. If an investment increases from \$1,000 to \$1,200 in a year, what is the percentage increase?

### A. Real-World Problem-Solving Questions

Here are the solutions and explanations for each of the practice problems:

1. The discount on the shirt is 25% of the original price, so we can use the formula percentage / 100 * whole to find the discount amount: 25 / 100 * 20 = \$5. The sale price is the original price minus the discount: \$20 – \$5 = \$15.
2. The change in population is 50,000 people, so we can use the formula change / original * 100% to find the percentage decrease: 50,000 / 500,000 * 100% = 10% decrease.
3. The change in investment is \$200, so we can use the formula change / original * 100% to find the percentage increase: 200 / 1,000 * 100% = 20% increase.

## V. Tips and Tricks for Finding Percentages

Here are some tips and tricks to help you find percentages more easily:

### A. Rounding Numbers

When you’re dealing with large numbers or decimals, it can be helpful to round the numbers before calculating the percentage. For example, if you’re trying to find the percentage of 65 out of 168, rounding to 70 out of 170 can make the calculation simpler.

### B. Memorizing Simple Multiplication Tables

Memorizing simple multiplication tables, such as 10%, 25%, 50%, and 75%, can make calculating percentages much easier. For example, 10% of a number is simply one-tenth of the number.

• Understanding basic fractions and decimals can make calculating percentages easier.
• Using online tools and calculators can save time and effort.
• Practicing and reviewing percentages regularly can help maintain skills.

## VI. Resources for Finding Percentages

If you need extra help or practice with finding percentages, several online resources are available:

### A. Online Percentage Calculators

Online percentage calculators can help you quickly and easily find percentages for a variety of problems. Some popular options include:

### B. Interactive Quizzes

Interactive quizzes can provide a fun and engaging way to practice finding percentages. Some popular options include:

## VII. Conclusion

### of Key Takeaways

Understanding how to find percentages is an important skill that can be used in many areas of life, such as finance, health, and education. The three basic formulas for finding percentages are part/whole*100%, change/original*100%, and percentage/100*whole. By practicing with real-world examples and using tips and tricks such as rounding and memorizing simple multiplication tables, you can improve your percentage skills.

### B. Opportunities to Practice Calculating Percentages

Practice makes perfect when it comes to calculating percentages. Use the real-world practice problems provided in this article, along with online resources such as percentage calculators and interactive quizzes, to improve your percentage skills.

### C. Encouragement and Final Thoughts

Don’t be intimidated by percentages! With a little practice and some helpful resources, you can become a percentage pro in no time. Remember that percentages are a valuable tool for understanding and interpreting real-world data, so by improving your percentage skills, you’re improving your ability to make informed decisions in a variety of scenarios.