Finding 20 percent
Use double 10% or one fifth.
Quick answer
Finding 20 percent is easy! You can do it by finding 10 percent twice, or by finding one-fifth of the number. Both methods work for any amount.
Learning outcome
By the end of this page, you will be able to find 20 percent of any number by either:
- Finding 10 percent and doubling it
- Finding one-fifth of the number
Success signs:
- You can explain how to find 20 percent
- You can find 20 percent of 100, 50, 20, 30, 150, and 120
- You can use 20 percent to solve a problem in real life
- You can show your work with drawings or numbers
Why this matters
Knowing how to find 20 percent helps you in many everyday situations:
- When you're shopping and see a 20% discount
- When you share food with friends
- When you're saving up for something special
- When you're helping your parents cook or measure ingredients
- When you're playing games that involve scoring or splitting rewards
It's also a building block for understanding more complex maths like fractions, decimals, and ratios. The more you know about percentages, the better you'll do in school and in real life!
How it works
Let's break it down into simple steps:
- Step 1: Find 10 percent of the number
- Step 2: Double that amount to get 20 percent
Or, you can:
- Step 1: Divide the number by 5
- Step 2: That gives you 20 percent
Both ways are correct and easy to remember!
Examples you can see
Let's try a few examples together:
Example 1: What is 20% of 60?
Method 1: Find 10% then double it
- 10% of 60 = 6
- Double 6 = 12
So, 20% of 60 = 12
Method 2: Divide by 5
- 60 ÷ 5 = 12
So, 20% of 60 = 12
Example 2: What is 20% of 150?
Method 1: Find 10% then double it
- 10% of 150 = 15
- Double 15 = 30
So, 20% of 150 = 30
Method 2: Divide by 5
- 150 ÷ 5 = 30
So, 20% of 150 = 30
Example 3: What is 20% of 25?
Method 1: Find 10% then double it
- 10% of 25 = 2.5
- Double 2.5 = 5
So, 20% of 25 = 5
Method 2: Divide by 5
- 25 ÷ 5 = 5
So, 20% of 25 = 5
Try it as a mini adventure
Imagine you're planning a party and you want to give 20% of your cake to your friends. You have a big chocolate cake that weighs 1000 grams. You need to find 20% to share with your friends. Here's how you can do it:
- Step 1: Find 10% of 1000 grams
- Step 2: Double that amount
Let's do it together:
- 10% of 1000 = 100 grams
- Double 100 = 200 grams
You can give 200 grams of cake to your friends!
Now try this challenge: You have 80 sweets to share. How many sweets are 20% of 80?
- 10% of 80 = ?
- Double that = ?
Answer: 10% of 80 = 8, double = 16. So 20% of 80 = 16 sweets.
Common mistakes
Here are some mistakes kids often make and how to fix them:
Mistake 1: Forgetting to double the 10% amount
Incorrect: 10% of 50 = 5, so 20% = 5
Why it happens: Kids think 20% means just 10%.
Fix: Remember that 20% = 10% + 10%, so double the 10% amount!
Mistake 2: Dividing by 4 instead of 5
Incorrect: 20% of 40 = 40 ÷ 4 = 10
Why it happens: Confusing 20% with 25%.
Fix: 20% means 20 out of 100, which is the same as 1 out of 5. So divide by 5!
Mistake 3: Making a calculation error
Incorrect: 10% of 120 = 12, double = 24, so 20% = 24
Why it happens: Not checking the work carefully.
Fix: Use the other method to check your answer!
Parent and carer guide
Here's how you can help your child learn this concept in just 5-10 minutes:
- Start with easy numbers: Try 20% of 100 or 50 first
- Use real objects: Use coins, blocks, or food to show 20% visually
- Play a quick game: Give your child 100 sweets and ask them to find 20% to share
- Ask questions: "How did you find 20% of 60?"
- Check their work: Have them try both methods to see if they get the same answer
Don't worry if they make mistakes at first. It's normal to practice and get better!
Remember, this is a building block for bigger maths. If they understand 20%, they'll find 10%, 25%, 50%, and other percentages easier later.
Practice questions
- What is 20% of 50?
- What is 20% of 100?
- What is 20% of 30?
- What is 20% of 120?
- What is 20% of 75?
Answers:
- 20% of 50 = 10
- 20% of 100 = 20
- 20% of 30 = 6
- 20% of 120 = 24
- 20% of 75 = 15
FAQ
What does 20 percent mean?
20 percent means 20 out of 100. It's like having 20 pieces out of 100 pieces of something.
Can I use this method for any number?
Yes! You can find 20% of any number using either method. It works for 10, 100, 1000, or even 10000!
Why is 20% the same as dividing by 5?
Because 20% = 20/100 = 1/5. So finding 20% is the same as finding one-fifth of a number.
How can I remember this?
Think of it like this: 20% = 10% + 10%, so find 10% and double it. Or, remember that 20% = 1/5, so divide by 5!
What if the number is not a whole number?
That's okay! You can still find 20%. For example, 20% of 25 is 5, and 20% of 26 is 5.2.