Percentages %
📖 In short
A shop window sign says: “50% off”. And a phone says: “Battery 20%”. The % sign means “out of a hundred”. 50% means 50 out of every 100, which is half. Percentages are an easy way to compare parts.
🤩 Did you know?
- Water covers about 71% of the Earth's surface.
- A child's body is about 65% water.
- The % sign comes from a short way of writing an Italian word meaning “per hundred”.
- 100% of something is the whole thing, and 200% is double.
🔎 Find out more
🌟 Out of every hundred
Imagine a grid of 100 squares. If we color 25 of them, we've colored 25%. If we color the whole grid, we've colored 100%. And 0% means nothing at all.
🔍 Percentages to know
50% = a half, 25% = a quarter, 75% = three quarters and 10% = a tenth. If you know these, you can work out most discounts in your head.
💡 Working out a discount
A shirt costs 60 and the discount is 25%. A quarter of 60 is 15, so after the discount it costs 60 − 15 = 45. And to find 10% of any number, divide it by 10.
🎯 At school and in the weather
A teacher might say: “90% of pupils passed”, meaning 90 out of every 100. And the weather presenter says: “30% chance of rain”, meaning rain isn't likely but is possible.
🧮 Worked examples
- 50% of 80 = 40Half.
- 10% of 70 = 7Divide by 10.
- 25% of 40 = 10A quarter: 40 ÷ 4.
📚 Key words
- Percentage
- The number of parts out of every hundred, written with the % sign
- Discount
- An amount taken off the original price
- Probability
- How likely something is to happen
🧪 Try it at home
Draw a 10 × 10 grid (100 squares). Color 50% blue, 25% red and 10% green. How many squares are still white? And what percentage is that?
🧩 Test yourself
1 50% means…
2 What is 10% of 50?
3 If a phone battery is at 100%, it is…