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fractions

Unit fractions

Understand fractions with numerator 1, such as 1/2, 1/3 and 1/10.

Quick answer

A unit fraction is a fraction where the top number (numerator) is 1, like 1/2, 1/3, or 1/10. It means one part of something that has been split into equal pieces.

Learning outcome

By the end of this page, you will understand what unit fractions are and how to use them to describe parts of a whole. Success signs:
  • You can identify unit fractions from a list of fractions
  • You can draw a picture showing a unit fraction
  • You can explain what 1/4 means in real life
  • You can compare two unit fractions and say which is bigger

Why this matters

Unit fractions help us talk about parts of things in a simple way. When you share a pizza with friends, or split a cake between family members, you're using unit fractions. Understanding them helps you learn more about fractions later, like how to add and subtract fractions, and how to think about parts of a whole. Whether you're cooking, playing games, or sharing your toys, unit fractions are everywhere around you.

How it works

A fraction has two parts: the top number (numerator) and the bottom number (denominator). The denominator tells us how many equal parts something is divided into. The numerator tells us how many of those parts we are talking about. Unit fractions are special because the numerator is always 1. This means we're always talking about just one part of something that has been split into equal pieces. Let's look at some examples:
  1. 1/2 means one of two equal parts
  2. 1/3 means one of three equal parts
  3. 1/4 means one of four equal parts
  4. 1/10 means one of ten equal parts

Examples you can see

Let's imagine you have a chocolate bar and want to share it equally with your friends. Example 1: 1/2 of a chocolate bar If you split the bar into 2 equal pieces and take one piece, you have 1/2 of the bar. Example 2: 1/4 of a pizza If you cut a pizza into 4 equal slices and eat one slice, you've eaten 1/4 of the pizza. Example 3: 1/10 of a bag of sweets If you have 10 sweets in a bag and take 1 sweet, you've taken 1/10 of the bag. Here's a table showing how unit fractions work with different numbers:
Denominator (bottom number) Unit fraction What it means
2 1/2 One of two equal parts
3 1/3 One of three equal parts
4 1/4 One of four equal parts
5 1/5 One of five equal parts
6 1/6 One of six equal parts
7 1/7 One of seven equal parts
8 1/8 One of eight equal parts
9 1/9 One of nine equal parts
10 1/10 One of ten equal parts
11 1/11 One of eleven equal parts
12 1/12 One of twelve equal parts

Try it as a mini adventure

Adventure: The Fraction Bakery You are a young baker helping your grandpa in his bakery. He has a big chocolate cake that he wants to cut into equal pieces for a party. You have to help him figure out how to divide the cake fairly.
  1. First, he wants to cut the cake into 2 equal pieces. What fraction is each piece? Answer: 1/2
  2. Then, he wants to cut the cake into 4 equal pieces. What fraction is each piece? Answer: 1/4
  3. Next, he wants to cut the cake into 8 equal pieces. What fraction is each piece? Answer: 1/8
  4. Finally, he wants to cut the cake into 12 equal pieces. What fraction is each piece? Answer: 1/12
Now, if you had a cake and wanted to give one piece to each of your 5 friends, how many pieces would you need to cut it into? Answer: 5 pieces, so each friend gets 1/5 of the cake

Common mistakes

  • Mistake: Thinking 1/4 is bigger than 1/2 because 4 is bigger than 2.
    Why it happens: Children often focus only on the numbers in the fraction and not what they mean.
    Fix: Remember that the bigger the denominator (bottom number), the smaller each piece is. So 1/4 means one of four pieces, which is smaller than 1/2 which means one of two pieces.
  • Mistake: Not understanding that unit fractions are always one part of a whole.
    Why it happens: Confusion about what the numerator means.
    Fix: Practice drawing pictures of unit fractions to see that they always represent one part of something split equally.
  • Mistake: Believing that 1/10 is the same size as 1/2.
    Why it happens: Not realising that the bigger the number on the bottom, the smaller the pieces.
    Fix: Use physical objects like counters or blocks to show that 10 pieces are much smaller than 2 pieces when the whole is the same size.

Parent and carer guide

Help your child understand unit fractions by using everyday examples and hands-on activities. Here's how:
  • Use real objects: Share food like pizza or cake and talk about what fraction each person gets.
  • Draw pictures: Ask your child to draw a circle and split it into equal parts, then shade one part to show 1/3 or 1/4.
  • Play games: Use dice or cards to create unit fractions and compare them.
  • Count together: Count how many equal parts something has, like 8 pieces of fruit or 12 crayons.
  • Ask questions: "If we split this cake into 6 pieces, what fraction is each piece?"
Remember: It's okay if your child makes mistakes. They're learning! Focus on the thinking process, not just getting the right answer. If they say 1/4 is bigger than 1/2, don't just correct them. Ask: "How many pieces would we have if we split the cake into 4 pieces versus 2 pieces?"

Practice questions

  1. Which of these is a unit fraction: 2/3, 1/5, 3/4, or 1/8?
  2. Draw a picture showing 1/6 of a rectangle.
  3. What fraction of a pizza is each slice if the pizza is cut into 4 equal pieces?
  4. Is 1/3 bigger or smaller than 1/6? Explain your thinking.
  5. Write the unit fractions for denominators 1 through 5.
Answers:
  1. 1/5 and 1/8 are unit fractions because their numerators are 1.
  2. Draw a rectangle divided into 6 equal parts with 1 part shaded.
  3. Each slice is 1/4 of the pizza.
  4. 1/3 is bigger than 1/6. When you split something into 3 pieces, each piece is larger than when you split it into 6 pieces.
  5. 1/1, 1/2, 1/3, 1/4, 1/5

FAQ

What is a unit fraction?

A unit fraction is a fraction where the top number (numerator) is 1. Examples include 1/2, 1/3, 1/4, and 1/10.

Why are unit fractions important?

Unit fractions help us understand how to split things equally and form the foundation for learning more complex fractions. They are used in everyday life when sharing food or dividing items.

Can you give me more examples of unit fractions?

Yes! Other examples are 1/5, 1/7, 1/9, 1/12, and 1/100. Any fraction where the numerator is 1 is a unit fraction.

How do unit fractions relate to whole numbers?

When you have 1/2, 1/3, 1/4, etc., and you put them together, they can make a whole. For example, 1/4 + 1/4 + 1/4 + 1/4 = 1 whole.

Are all unit fractions the same size?

No, they are not. The larger the denominator, the smaller each unit fraction is. For example, 1/10 is smaller than 1/2 because ten pieces are smaller than two pieces when the whole is the same size.