Decimals Topic Guide for Teachers

Decimals are a useful way of representing parts of a whole. The largest part of the whole shown in a decimal is tenths, followed by hundredths, thousandths and so on, getting ten times smaller each time.

In most countries, the system of money is based on decimals. In the UK, this means that pounds are represented as whole numbers and pennies as parts of a pound. This works because there are 100 pennies in a pound (or 100 cents in a dollar or a euro), so 1 penny = 1 hundredth of a pound. When you see an amount of money, for example £1.85, it means 1 whole pound and 85/100 of a pound (i.e. 85p).

Teach your children about decimals using our handy topic guide!

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Teaching Ideas

Tackle some decimal word problems.
Use these differentiated sheets for addition and subtraction of decimals.
Divide your class up into teams and see which team can work through these addition and subtraction questions the fastest.
Try this fantastic idea for introducing decimals that are larger than 1.0.
Try one of these ideas for decimals larger than 2.0.
Use these activities to introduce and consolidate counting in units, tenths and hundredths.
Work in pairs on this decimal spiral game from NRICH.
Use this game to work on ordering decimals – there are lots of options so it is easy to find the right level for your children.

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Resources

Download our huge Decimals Pack for plenty of resources, including a decimals guide and audio quizzes!

This useful file includes 16 cards showing a fraction and the equivalent decimal and percentage, as well as a diagram.
Help your children to visualise tenths and hundredths with this simple frame.
These printable decimal number lines are perfect for supporting children when working with decimals.
Visit the BBC Bitesize decimals page for lots of information and videos.

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Decimals Facts

When we talk about decimals, we usually mean decimal fractions. Our number system is also known as decimal because it is based on 10s.
Digits to the left of the decimal point represent whole numbers (integers), while digits to the right represent parts of numbers. For example 1.5 equals 1 whole and 5 tenths, or 11/2.
When there is no whole number, 0 is usually used as a place holder, as in 0.25 (a quarter).
Although they were written differently, decimal fractions are believed have been used in China during the fourth century BCE.
The system we now use for writing decimals was developed during the 17th century by Simon Stevin, a Belgian mathematician.

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Videos

What is a Decimal?

This short video gives a brief overview of decimals, especially their relationship to fractions.

Running time: 3:58

Decimal Point Video for Kids

This video is perfect for teaching children how to read decimals correctly.

Running time: 2:24

Converting fractions, decimals and percentages

This lively Decimal Dance Off is a great way to introduce the concept of converting fractions, decimals and percentages.

Running time: 3:52

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Books

Links

Topmarks have a collection of games for fractions and decimals on this page.
Match decimals to fractions and percentages with this differentiated game.
Visit the Maths is Fun decimals page for lots of decimal worksheets.
How quickly can you add the decimals in this hungry puppy game?
Match the decimal words to the correct value while the puppies play tug of war!
This page leads to two great games, one for comparing decimals and another for ordering them. The decimals are to 2 decimal places.