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Place Value

Decimal place value to tenths

Introduce one tenth as one part of a whole split into ten.

Quick answer

Decimal place value to tenths means understanding that one tenth is one part when you split a whole into ten equal parts. You can write this as 0.1 or 1/10.

Learning outcome

By the end of this page, you will understand how to show one tenth using decimal notation and be able to identify tenths in everyday objects and situations. Success signs:
  • You can say what 0.1 means in words
  • You can point to one tenth of a shape or object
  • You can write 0.1 as a fraction and a decimal
  • You can explain how tenths relate to whole numbers

Why this matters

Decimal place value to tenths helps you understand money (like 20p is 0.20 of a pound), measurements (like 0.5m is half a metre), and sharing (like 0.1 of a pizza is one tenth). It's the first step in learning more complex decimals, which you'll use in science, cooking, and shopping.

How it works

Decimal place value to tenths is about splitting a whole number into ten equal parts. Each part is one tenth. When you write it as a decimal, it looks like this: 0.1. The 0 is the whole number part, and the 1 is in the tenths place. Think of it like sharing a cake. If you cut one cake into ten equal pieces, each piece is one tenth of the cake. If you eat one piece, you've eaten 0.1 of the cake. You can also think of tenths in terms of money. If you have 10p, that's one tenth of a pound. If you have 100p, that's one pound. So 10p is 0.10 of a pound.

Examples you can see

Let's look at some examples using shapes, money, and everyday objects. Example 1: Cake sharing Imagine one whole cake. If you cut it into ten equal pieces, each piece is one tenth.
  • One piece = 1/10 or 0.1 of the cake
  • Two pieces = 2/10 or 0.2 of the cake
  • Five pieces = 5/10 or 0.5 of the cake
Example 2: Money If you have 10p, that's one tenth of a pound.
  • 10p = 0.10 of a pound
  • 20p = 0.20 of a pound
  • 50p = 0.50 of a pound
Example 3: Number line On a number line from 0 to 1, if you divide it into ten equal parts:
  • First mark = 0.1
  • Second mark = 0.2
  • Third mark = 0.3
  • Fourth mark = 0.4
  • Fifth mark = 0.5
  • Sixth mark = 0.6
  • Seventh mark = 0.7
  • Eighth mark = 0.8
  • Ninth mark = 0.9
  • Tenth mark = 1.0

Try it as a mini adventure

The Decimal Treasure Hunt You are a young explorer looking for treasure in a magical land where everything is measured in tenths! Step 1: The map Your map shows a path from 0 to 1. You must find the treasure at 0.5. You start at 0 and move forward by tenths. Step 2: The journey You walk:
  • First step: 0.1
  • Second step: 0.2
  • Third step: 0.3
  • Fourth step: 0.4
  • Fifth step: 0.5
Step 3: The treasure At 0.5, you find a chest filled with coins. Each coin is worth 0.1 of a pound. How many coins are in the chest if it's worth 0.5 pounds? Step 4: The challenge Now, you need to find the treasure at 0.8. How many steps did you take to get there?

Common mistakes

  • Mistake: Thinking 0.1 means 1 whole
    Why it happens: Confusing decimal place value with whole numbers
    Fix: Remember that 0.1 means one part out of ten equal parts
  • Mistake: Writing 0.1 as 1.0
    Why it happens: Not understanding the decimal point position
    Fix: The decimal point separates whole numbers from parts. 0.1 is one tenth, not one whole
  • Mistake: Counting tenths as if they were whole numbers
    Why it happens: Not understanding that 0.1, 0.2, 0.3 are smaller than 1
    Fix: Use a number line or visual representation to show that tenths are less than 1

Parent and carer guide

Helping your child understand decimal place value to tenths doesn't require fancy tools. Here are 5 minutes of practical support: What to say:
  • "Let's look at this shape. If we split it into ten equal parts, what is one part called?"
  • "How many 10p coins make 50p? What decimal is that?"
  • "Can you show me 0.3 on a number line?"
What not to worry about:
  • Your child might think 0.1 is bigger than 0.5 at first. This is normal.
  • Don't rush to correct every mistake. Let them explore and make discoveries.
  • It's okay if they need to count or draw to understand.
How to help:
  • Use everyday objects like coins, pizza slices, or blocks to show tenths
  • Draw number lines and mark tenths together
  • Play simple games like "What's the decimal?" using a number line

Practice questions

  1. What is one tenth written as a decimal?
  2. How many tenths make one whole?
  3. Write 0.7 as a fraction
  4. What decimal is 3 tenths?
  5. Which is bigger: 0.4 or 0.6?
Answers:
  1. 0.1
  2. 10 tenths
  3. 7/10
  4. 0.3
  5. 0.6

FAQ

What does "tenths" mean?

Tenths mean one part when you split something into ten equal parts.

How do you write one tenth as a decimal?

You write one tenth as 0.1. The 1 is in the tenths place.

Can you give me a real-life example of tenths?

Yes! If you have 10p, that's one tenth of a pound. If you eat 1 slice from a pizza cut into 10 slices, you've eaten one tenth of the pizza.

Why is learning tenths important?

Learning tenths helps you understand money, measurements, and fractions. It's the foundation for learning more complex decimals later.

How can I practice tenths at home?

You can use coins, pizza slices, or blocks to show tenths. Draw number lines and mark tenths. Ask questions like "What is 0.3 of a pizza?"