Ratio for primary learners

Quick answer

Ratio compares how much of one thing there is compared to another thing. You can say "for every 2 red cars, there is 1 blue car" or "the ratio of red cars to blue cars is 2 to 1".

Learning outcome

By the end of this page, you will be able to compare two groups of things using ratio language like "for every" and "to".

• You can describe how many of one thing there are compared to another.
• You can use the words "for every" and "to" to explain ratios.
• You can match ratios to pictures or real-life examples.
• You can start to see patterns in ratios.

Why this matters

Understanding ratios helps you describe things in everyday life, like how many people are in your class compared to how many teachers, or how many ingredients are in your favourite recipe. Ratios are used in cooking, sport, art, and even in video games to make things look right. They help you think about how things relate to each other in a clear way.

How it works

When we use ratio, we are comparing two amounts. We can do this in two ways:

1. Using "for every" – like "for every 3 red balloons, there are 2 blue balloons"
2. Using "to" – like "the ratio of red balloons to blue balloons is 3 to 2"

We can also show ratios with pictures or objects. For example, if you have 4 apples and 2 oranges, you can say:

• For every 2 apples, there is 1 orange
• The ratio of apples to oranges is 4 to 2

Examples you can see

Let’s imagine you have a bag of sweets. In your bag, there are 6 chocolate sweets and 3 strawberry sweets.

You can describe this using ratio in these ways:

• For every 2 chocolate sweets, there is 1 strawberry sweet
• The ratio of chocolate to strawberry sweets is 6 to 3

Here is a picture you can imagine:

You can see that there are 2 groups of 3 chocolate sweets for every 1 group of 3 strawberry sweets. This means the ratio is 6 to 3.

Another example: In your classroom, there are 10 boys and 5 girls.

• For every 2 boys, there is 1 girl
• The ratio of boys to girls is 10 to 5

Try to think of your own examples. How many books are on your shelf compared to how many pencils? How many red flowers are there compared to blue flowers?

Try it as a mini adventure

Imagine you are a space explorer on a mission to collect alien fruits. You find a tree with 8 purple fruits and 4 green fruits.

Your mission is to report the ratio of purple to green fruits back to Earth.

1. First, count how many purple fruits there are: 8
2. Then, count how many green fruits there are: 4
3. Now, compare them using "for every": For every 2 purple fruits, there is 1 green fruit
4. Write the ratio using "to": The ratio of purple to green fruits is 8 to 4

Can you find other trees with different ratios? Draw your own alien fruit trees and write the ratios!

Common mistakes

• Mistake: Saying "the ratio of 6 to 3 is 3 to 1" instead of 2 to 1
  Why it happens: Children might divide the numbers without simplifying the ratio properly.
  Fix: Make sure to find the same number that goes into both numbers evenly. 6 and 3 both divide by 3, so 6 ÷ 3 = 2 and 3 ÷ 3 = 1. The ratio is 2 to 1.
• Mistake: Writing the ratio backwards, like "for every 1 blue, there are 3 red" when there are 3 red and 1 blue
  Why it happens: Children might get confused about which group comes first.
  Fix: Always check which group is first in your sentence. If you have 3 red and 1 blue, say "for every 3 red, there is 1 blue".
• Mistake: Mixing up "for every" and "to"
  Why it happens: These phrases are similar but used differently.
  Fix: "For every" is used in sentences like "for every 2 cats, there is 1 dog". "To" is used in "the ratio is 2 to 1".

Parent and carer guide

Helping your child understand ratio is about making it fun and real. Here are some ways to support your child:

• Use everyday examples like "for every 2 socks you wear, there is 1 sock left in the drawer"
• Draw pictures or use toys to show ratios
• Play games where you compare groups of things
• Ask your child to explain a ratio they see in the world around them
• Don’t worry if they get it wrong at first – it’s part of learning!

Remember, children learn best when they're actively involved. Try to make ratio feel like a game or a story, not a test.

Practice questions

1. There are 5 red marbles and 10 blue marbles. What is the ratio of red to blue marbles?
   Answer: 5 to 10 or 1 to 2
2. For every 4 green leaves, there are 2 yellow leaves. What is the ratio of green to yellow leaves?
   Answer: 4 to 2 or 2 to 1
3. There are 12 blue toys and 6 red toys. What is the ratio of red to blue toys?
   Answer: 6 to 12 or 1 to 2
4. For every 3 cats, there is 1 dog. What is the ratio of cats to dogs?
   Answer: 3 to 1
5. There are 7 yellow flowers and 7 blue flowers. What is the ratio of yellow to blue flowers?
   Answer: 7 to 7 or 1 to 1

FAQ

What is a ratio?
A ratio is a way to compare how much of one thing there is compared to another thing.

How do I write a ratio?
You can write a ratio using words like "for every" or "to". For example, "for every 2 red cars, there is 1 blue car" or "the ratio of red to blue cars is 2 to 1".

Can ratios be simplified?
Yes! Just like fractions, ratios can be simplified. For example, 6 to 3 can be simplified to 2 to 1.

Why do we use ratios?
Ratios help us describe how things relate to each other. They are used in cooking, sport, art, and many other areas of life.

Can I use ratios with any numbers?
Yes! You can compare any two groups of things using ratios, as long as you can count them clearly.