February 20, 2023

How are percentages calculated?

Introduction

Hey there, young scholars! Today, we're going to learn about something we use in our everyday lives: percentages! You might have come across them while shopping, watching sports, or even comparing your test scores with your classmates. So, let's dive into the world of percentages and discover how they are calculated.

What is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. It's used to compare different amounts or show a proportion. The word "percentage" comes from the Latin word "per centum," which means "by the hundred." In short, when you see a percentage, it's telling you how many parts there are out of 100.

For example, if you scored 80% on a test, it means you got 80 out of 100 possible points. Pretty neat, right?

How to Calculate Percentages

Calculating percentages is super easy! All you need to do is follow these three simple steps:

  1. Divide the part (the amount you want to find the percentage of) by the whole (the total amount).
  2. Multiply the result by 100.
  3. Write down the result with the percentage symbol (%).

Let's work through an example together:

Imagine that there are 30 students in your class, and 15 of them are girls. To find the percentage of girls in the class, we can use the three steps we just learned:

  1. Divide the part (the number of girls) by the whole (the total number of students): 15 ÷ 30 = 0.5
  2. Multiply the result by 100: 0.5 × 100 = 50
  3. Write down the result with the percentage symbol: 50%

So, 50% of the students in your class are girls!

Percentage Problems

Now that you know how to calculate percentages let's try some more examples:

  1. You just finished a 20-question quiz and got 16 questions right. What percentage of questions did you answer correctly?
  • Divide the part (16) by the whole (20): 16 ÷ 20 = 0.8
  • Multiply the result by 100: 0.8 × 100 = 80
  • Write down the result with the percentage symbol: 80%

You answered 80% of the questions correctly!

  1. Your favourite football team won 18 games out of 30. What percentage of games did they win?
  • Divide the part (18) by the whole (30): 18 ÷ 30 = 0.6
  • Multiply the result by 100: 0.6 × 100 = 60
  • Write down the result with the percentage symbol: 60%

Your favourite football team won 60% of their games!

Finding the Original Amount

Sometimes, you'll come across problems where you know the percentage, but you need to find the original amount. To do this, follow these steps:

  1. Divide the percentage by 100.
  2. Multiply the result by the total amount.

For example, imagine that you know that 25% of the students in your school play a musical instrument, and there are 800 students in total. How many students play an instrument?

  1. Divide the percentage (25%) by 100: 25 ÷ 100 = 0.25
  2. Multiply the result by the total number of students (800): 0.25 × 800 = 200

So, 200 students play a musical instrument!

Conclusion

Percentages are super useful and can be found everywhere in our daily lives, from shopping discounts to measuring progress in school subjects. Now that you know how to calculate percentages, you're equipped with an essential skill that will serve you well in both your academic and personal life. Remember the three simple steps we've covered, and you'll be a percentage pro in no time! So, keep practicing and exploring the wonderful world of percentages. Happy calculating!

Think Smart Academy

Over 10 years of experience

Contact Think Smart Academy Today

We invite you to our Slough tuition centre, for a presentation and walk though on how we will help your child pass their exam.