Fractions: halves, thirds and quarters
📖 In short
Mom cut the pizza into 4 equal slices and I ate one: I ate a “quarter” of the pizza, which we write 1/4. A fraction describes part of something split into equal parts. We use fractions when sharing food, telling the time and cooking.
🤩 Did you know?
- A quarter of an hour is 15 minutes, and half an hour is 30 minutes.
- The ancient Egyptians used fractions about 4000 years ago to share bread and land.
- The line between the numerator and denominator was introduced by Arab scholars, including al-Hassar from the Maghreb.
- Four quarters make one whole: the whole pizza.
🔎 Find out more
🌟 Numerator and denominator
In the fraction 3/4, the bottom number 4 is called the “denominator”: how many parts we cut the thing into. The top number 3 is called the “numerator”: how many parts we take. So 3/4 is three parts out of four.
🔍 The parts are equal
If we cut an apple into two pieces, one big and one small, neither is a half! A fraction always means exactly equal parts.
💡 Equal fractions
Half a pizza is the same as two quarters: 1/2 = 2/4 = 4/8. Multiplying the numerator and denominator by the same number gives an equal fraction, as if we cut the slices into smaller pieces.
🎯 Which is bigger?
The bigger the denominator, the smaller the piece: 1/8 is smaller than 1/4, because the pizza was cut into more pieces. And if the denominators are the same, the bigger fraction has the bigger numerator: 3/5 is bigger than 2/5.
📊 See it in a picture
🧮 Worked examples
- 1/2 = 2/4 = 3/6Three ways to write a half.
- 1/4 of 20 = 5We divide 20 by 4.
- 3/4 of 20 = 15A quarter is 5, so three quarters is 3 × 5 = 15.
📚 Key words
- Fraction
- Part of something split into equal parts
- Denominator
- The bottom number: how many parts in all
- Numerator
- The top number: how many parts we take
🧪 Try it at home
Fold a square of paper in half, then into four quarters, then into eight eighths. Color 3/8 of it, then find out: how many eighths are in a quarter?
🧩 Test yourself
1 A cake was cut into 3 equal pieces and we ate one. What fraction did we eat?
2 Which is bigger?
3 A half is the same as…