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Child-friendly Decimal vocabulary

Child-friendly definitions and examples for words such as decimal point, tenth, hundredth, thousandth and place value.

Quick answer

Decimal vocabulary helps you understand numbers that have parts, like 0.5 or 3.25. Key words include decimal point, tenth, hundredth, and thousandth, which help you read and write numbers with parts.

Learning outcome

By the end of this page, you will be able to identify and use decimal vocabulary to understand numbers that have parts, like 0.7 or 2.34. Success signs:
  • You can say what the decimal point means
  • You can identify the tenths and hundredths in a decimal number
  • You can read decimal numbers out loud
  • You can explain how decimal numbers are different from whole numbers

Why this matters

Decimal vocabulary is important because it helps you understand money, measurements, and many real-life situations where numbers have parts. For example, when you buy something that costs £2.50, or when you measure how tall you are in metres and centimetres, you are using decimal numbers. Understanding these words helps you make sense of numbers that are not just whole numbers like 1, 2, 3.

How it works

Decimal numbers have a decimal point (a small dot) that separates the whole part from the part part. For example, in 3.45, the 3 is the whole part and the 45 is the part part. The numbers to the right of the decimal point show how many tenths, hundredths, or thousandths of a whole you have. Let's look at how decimal numbers work step by step:
  1. Whole numbers are on the left side of the decimal point
  2. The first digit to the right of the decimal point is the tenths
  3. The second digit to the right is the hundredths
  4. The third digit to the right is the thousandths

Examples you can see

Let's explore decimal vocabulary with some examples you can imagine or draw. Example 1: The decimal point If you have the number 4.7, the decimal point is the dot between 4 and 7. It shows that 4 is the whole number part and 7 is the part part. Example 2: Tenth If you have 0.3, this means 3 tenths. Imagine 3 of 10 equal pieces of a whole. You can draw a square and divide it into 10 parts. Then shade 3 parts. That shows 0.3 or 3 tenths. Example 3: Hundredth If you have 0.25, this means 25 hundredths. Imagine 25 of 100 equal pieces of a whole. You can draw a square and divide it into 100 parts. Then shade 25 parts. That shows 0.25 or 25 hundredths. Example 4: Thousandth If you have 0.007, this means 7 thousandths. Imagine 7 of 1000 equal pieces of a whole. This is a very small part. You can imagine a cube divided into 1000 small cubes and shade 7 of them.

Try it as a mini adventure

Adventure: The Decimal Detective You are a detective looking for clues about decimal numbers in your home. Your mission is to find 3 decimal numbers and write down what each part means. 1st time: Look in your kitchen for a price tag. What does the decimal point mean in that number? 2nd time: Find a ruler or measuring tape. What does the decimal part of a measurement mean? 3rd time: Look at a clock. What does the decimal part of time mean? 4th time: Draw a decimal number like 0.6 or 1.25 and explain what each digit means. 5th time: Think of a real-life situation where you use decimal numbers.

Common mistakes

  • Mistake: Thinking that 0.5 means 5 whole things
    Why it happens: Confusing the decimal point with a separator that changes the meaning
    Fix: Remember that 0.5 means 5 tenths, which is half of one whole thing
  • Mistake: Saying "0.25 is 25 whole things"
    Why it happens: Not understanding that numbers after the decimal point are parts of a whole
    Fix: Remember that 0.25 means 25 hundredths, which is a small part of one whole thing
  • Mistake: Counting the decimal point as a number
    Why it happens: Not knowing the decimal point's special job as a separator
    Fix: The decimal point just shows where the whole part ends and the part part begins
  • Mistake: Reading 0.7 as "seven tenths" but saying "point seven"
    Why it happens: Mixing up how to read decimal numbers
    Fix: Read 0.7 as "zero point seven" or "seven tenths"

Parent and carer guide

As a parent or carer, you can help your child understand decimal vocabulary by:
  • Using everyday examples like money (£0.25) or measurements (1.5 kg)
  • Practicing reading decimal numbers out loud together
  • Using visual aids like drawing squares divided into 10 or 100 parts
  • Playing games where you say a decimal number and your child identifies the tenths and hundredths
  • Encouraging your child to explain decimal numbers in their own words
  • Reassuring them that decimal numbers are just another way to show parts of a whole
Remember that it's normal for children to mix up decimal vocabulary at first. Be patient and keep practicing with fun examples from daily life.

Practice questions

  1. What does the decimal point separate in the number 6.82?
  2. How many tenths are in 0.4?
  3. What does the digit 5 mean in 0.57?
  4. How many hundredths are in 0.36?
  5. Write the decimal number that shows 8 tenths and 9 hundredths
Answers:
  1. The whole part from the part part
  2. 4 tenths
  3. 5 hundredths
  4. 36 hundredths
  5. 0.89

FAQ

What is a decimal point?

The decimal point is a small dot that separates the whole number part from the part part in a decimal number.

What does "tenth" mean?

A tenth means one of ten equal parts of a whole thing. For example, 0.3 means 3 tenths.

What does "hundredth" mean?

A hundredth means one of one hundred equal parts of a whole thing. For example, 0.25 means 25 hundredths.

What does "thousandth" mean?

A thousandth means one of one thousand equal parts of a whole thing. For example, 0.007 means 7 thousandths.

How are decimal numbers different from whole numbers?

Whole numbers are complete numbers like 1, 2, 3, while decimal numbers have parts, like 1.5 or 2.75.