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decimals

Rounding decimals

Round decimals to whole numbers, tenths or hundredths.

Quick answer

Rounding decimals means making a decimal number simpler by changing it to the nearest whole number, tenth, or hundredth. You look at the digit after the place you want to round to and decide whether to stay the same or go up.

Learning outcome

By the end of this page, you will be able to round decimals to the nearest whole number, tenth, or hundredth using the correct method. Success signs:
  • You can look at a decimal number and decide which whole number it is closest to
  • You can round a decimal to the nearest tenth by looking at the hundredths digit
  • You can round a decimal to the nearest hundredth by looking at the thousandths digit
  • You can explain why you rounded a decimal in a simple way

Why this matters

Rounding decimals is useful in everyday life because it helps us make quick estimates and simplifies numbers for easier calculations. You might round prices when shopping, measurements when cooking, or scores in games. It's also important in science, money, and maps where exact numbers aren't always needed or practical.

How it works

Rounding decimals is like deciding whether to go up or down when you're near a number. Here's how:
  1. Decide which place you want to round to (whole number, tenth, or hundredth)
  2. Look at the digit just to the right of your rounding place
  3. If that digit is 5 or more, round up (go to the next higher number)
  4. If that digit is less than 5, round down (stay at the same number)

Examples you can see

Let's look at some examples using the number 3.674. Rounding to the nearest whole number:
  • Look at the tenths place: 6
  • Since 6 is more than 5, we round up
  • 3.674 rounds to 4
Rounding to the nearest tenth:
  • Look at the hundredths place: 7
  • Since 7 is more than 5, we round up
  • 3.674 rounds to 3.7
Rounding to the nearest hundredth:
  • Look at the thousandths place: 4
  • Since 4 is less than 5, we round down
  • 3.674 rounds to 3.67

Try it as a mini adventure

Adventure: The Decimal Island Rescue You are a brave explorer on a mysterious island where numbers live. You find a decimal number floating in a pool of water. The number is 7.283. The island's guide says you must round it to help it find its way home. You have three choices:
  1. Rounding to the nearest whole number
  2. Rounding to the nearest tenth
  3. Rounding to the nearest hundredth
Your mission is to help the number find its way home by rounding it correctly. Step 1: Rounding to the nearest whole number
  • Look at the tenths digit: 2
  • 2 is less than 5, so round down
  • 7.283 rounds to 7
Step 2: Rounding to the nearest tenth
  • Look at the hundredths digit: 8
  • 8 is more than 5, so round up
  • 7.283 rounds to 7.3
Step 3: Rounding to the nearest hundredth
  • Look at the thousandths digit: 3
  • 3 is less than 5, so round down
  • 7.283 rounds to 7.28
You have successfully helped the decimal number find its way home!

Common mistakes

  • Mistake: Looking at the wrong digit when rounding
    • Why it happens: Children may confuse which digit to look at for rounding
    • Fix: Always look at the digit immediately to the right of your rounding place
  • Mistake: Forgetting that 5 rounds up
    • Why it happens: Children might think 5 is "in the middle" and stay the same
    • Fix: Remember: 5 or more, round up. Less than 5, round down
  • Mistake: Not keeping all the digits when rounding
    • Why it happens: Children might forget to keep the digits to the left of the rounded place
    • Fix: When rounding to a specific place, keep all digits to the left and change only the rightmost one
  • Mistake: Confusing tenths and hundredths
    • Why it happens: Children may mix up the decimal places
    • Fix: Remember: tenths are first after the decimal point, hundredths are second

Parent and carer guide

As a parent or carer, you can help your child understand rounding decimals by:
  • Using real-life examples like prices, measurements, or scores
  • Practising with everyday numbers like 3.45, 7.82, or 12.99
  • Playing a rounding game where you give a decimal and ask them to round it
  • Reinforcing the rule: 5 or more, round up; less than 5, round down
  • Checking that they understand which digit to look at
It's normal for children to make mistakes at first. Be patient and encouraging. Remember that rounding is a skill that improves with practice.

Practice questions

  1. Round 4.67 to the nearest whole number
  2. Round 8.34 to the nearest tenth
  3. Round 2.187 to the nearest hundredth
  4. Round 5.923 to the nearest whole number
  5. Round 1.456 to the nearest tenth
Answers:
  1. 5
  2. 8.3
  3. 2.19
  4. 6
  5. 1.5

FAQ

What does it mean to round a decimal?

Rounding a decimal means making it simpler by changing it to the nearest whole number, tenth, or hundredth. You look at the digit after the place you want to round to and decide whether to go up or down.

How do I know which digit to look at when rounding?

Look at the digit just to the right of where you want to round. For example, if rounding to the nearest tenth, look at the hundredths digit.

Why does 5 round up?

The rule is: 5 or more, round up. This is a standard mathematical convention that makes rounding consistent and predictable.

Can I round decimals to any place?

Yes! You can round to any decimal place: whole numbers, tenths, hundredths, thousandths, and so on.

What happens if I round 5.5 to the nearest whole number?

5.5 rounds to 6 because the tenths digit is 5, which means round up according to the rule.