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Maths Adventures

Fairground maths quest: decimals

A story-led junior maths adventure using rides, tickets and chance games to measure small distances, money and scores with tenths and hundredths.

Quick answer

Decimals are numbers that show parts of a whole, like 0.5 (half) or 0.25 (a quarter). In a fairground, you’ll see decimals when measuring small distances, counting tickets, or scoring points – and you can use them to add, subtract, and compare amounts of money.

Learning outcome

By the end of this page, you will be able to use decimals to measure small amounts of money, distance, and scores – like how much a ticket costs, how far a ride goes, or how many points you score in a game. Success signs:
  • You can read and write decimals like 0.5 and 0.25
  • You can compare decimals to see which is bigger or smaller
  • You can add and subtract decimals with the same number of decimal places
  • You can use decimals in real life, like counting your money or measuring a ride

Why this matters

Decimals are everywhere – especially in a fairground! Whether you're buying a ticket for £1.50, measuring how far a rollercoaster goes in metres, or scoring points in a ring toss game, decimals help you be precise. Understanding decimals is important for maths at school and for real-life situations like shopping, cooking, or measuring things at home.

How it works

Decimals are numbers that are less than one whole. They use a decimal point (.) to separate the whole number from the parts. For example:
  • 0.1 means one-tenth (like 1 out of 10)
  • 0.01 means one-hundredth (like 1 out of 100)
Think of a pizza cut into 10 equal slices. If you eat 3 slices, you’ve eaten 0.3 of the pizza. If you eat 3 out of 100 slices, that’s 0.03 of the pizza.

Examples you can see

Let’s imagine you’re at a fairground with these decimals: Example 1: Tickets You buy 3 tickets, each costing £1.25. To find the total cost, you add: £1.25 + £1.25 + £1.25 = £3.75 You can think of this as: 1 + 1 + 1 = 3 (whole pounds) 0.25 + 0.25 + 0.25 = 0.75 (pennies) Example 2: Distance on a ride A Ferris wheel goes up 1.5 metres and down 1.5 metres. Total distance = 1.5 + 1.5 = 3.0 metres The 0 at the end doesn’t change the value, so 3.0m = 3m. Example 3: Ring toss game You score 0.7 points for one ring, and 0.3 points for another. Total points = 0.7 + 0.3 = 1.0 point This is the same as 1 whole point! Example 4: Comparing prices A funnel cake costs £1.20 and a cotton candy costs £1.15. Which is more expensive? Look at the tenths place: 2 tenths (0.2) vs 1 tenth (0.1) So £1.20 > £1.15

Try it as a mini adventure

Adventure: The Fairground Challenge You are on a mission to win a prize at the fairground. You have £2.50 in your pocket and need to buy tickets and play games. Step 1: You buy a ticket for £1.30. How much money do you have left? £2.50 - £1.30 = £1.20 Step 2: You play a ring toss game. You score 0.8 points and 0.2 points. Total points = 0.8 + 0.2 = 1.0 point Step 3: You buy a drink for £0.75. How much money do you have left? £1.20 - £0.75 = £0.45 Step 4: You play a game that costs 0.50p (50p). Can you afford it? £0.45 > £0.50? No, you don’t have enough. Step 5: You win a prize! You spent £1.30 + £0.75 = £2.05 You had £2.50, so you have £0.45 left.

Common mistakes

  • Mistake: Thinking 0.5 is bigger than 0.25 because 5 is bigger than 2. Why: Children often compare digits without thinking about place value. Fix: Remember that 0.25 is 25 hundredths, which is smaller than 0.5 (50 hundredths).
  • Mistake: Adding 0.5 + 0.3 = 0.80 Why: Children might add the digits and ignore the decimal point. Fix: Think of it as 5 tenths + 3 tenths = 8 tenths, or 0.8
  • Mistake: Writing 0.5 as 0.500 Why: Some children think adding zeros makes the number bigger. Fix: 0.5 = 0.50 = 0.500 – they’re all the same value!

Parent and carer guide

Parents and carers can help by:
  • Using real money to show how £1.50 works – split it into £1 and 50p
  • Playing fairground games at home using toy money or play tickets
  • Measuring small distances with a ruler and talking about tenths (e.g., 3.5 cm)
  • Using decimal numbers in everyday life like cooking or shopping
  • Encouraging children to explain how they solved a decimal problem
How to help without pressure: - Don’t rush – let them work at their own pace - Ask questions like “How did you figure that out?” or “Can you show me how you added that?” - Celebrate effort, not just correct answers - Keep it fun and playful – not like a test

Practice questions

  1. What is 0.4 + 0.3? Answer: 0.7
  2. Which is bigger: 0.6 or 0.55? Answer: 0.6
  3. How much is 2.10 + 0.90? Answer: 3.00
  4. You have £1.25 and spend £0.80. How much do you have left? Answer: £0.45
  5. What is 0.35 + 0.25? Answer: 0.60

FAQ

What are decimals?

Decimals are numbers that show parts of a whole. They use a decimal point (.) to separate the whole number from the parts. For example, 0.5 means half, and 0.25 means a quarter.

How are decimals used at the fairground?

Decimals are used to measure small amounts of money, distance, and scores. For example, a ticket costs £1.25, a ride goes 2.5 metres, and a ring toss game scores 0.8 points.

Can I add decimals like regular numbers?

Yes! You can add decimals the same way you add whole numbers, as long as you keep the decimal points lined up.

How do I know which decimal is bigger?

Compare the digits from left to right. Start with the tenths place (the first number after the decimal point). If those are the same, compare the hundredths place (the second number after the decimal point).

Why do we use decimals?

Decimals help us be precise when measuring small amounts. They’re used in money, science, cooking, and many other real-life situations.