CBSE Class 6 Maths Revision Notes Chapter 8

CBSE Class 6 Mathematics Chapter 8 Revision Notes – Decimals

Class 6 Mathematics Chapter 8 Notes focus on various concepts related to decimals. This chapter is important as it deals with the elementary concepts that are the building blocks for a solid foundation in advanced mathematics.

At Extramarks, subject matter experts, who are highly skilled and experienced in analysing the current trend of questions in CBSE exams, prepare these revision notes.  They make sure that all the key concepts are covered in these notes so that students can revise the entire chapter effectively by going through the notes.

Class 6 Mathematics Chapter 8 Notes provided by Extramarks are easily available on the website. Referring to these notes has numerous advantages will help students to get good grades  in the exams.

Access Class 6 Mathematics Chapter 8 – Decimals Notes


  • If an object or a collection of objects is divided into ten equal parts, then one part out of those ten parts is called the “tenth”.
  • The tenth part can be written as 1/10, that is, 0.1.
  • For example, take a piece of cardboard that is 10 cm 5 mm long. 1 cm is equal to 10 mm, and 1 mm is 1/10th of a cm, which is 0.1 cm. Therefore, 5 mm = 5/10 cm = 0.5 cm. The decimal representation of 10 cm 5 mm is 10.5 cm.


  • One out of every equally divided hundred parts is called the hundredth.
  • The decimal notation is 1/100 = 0.01.
  • If a rope is 9m 6 cm long, it can be represented in the following manner.  We know that 1 cm = 1/100 m = 0.01 m. Therefore, 6 cm = 6/100 m = 0.06 m. Therefore, the decimal representation of 9 m 6 cm = 9.06 m.

Representing Decimals on a Number Line

Decimals can be plotted on a number line like whole numbers, negative numbers, and integers.

  • Suppose, 0.6 is the given decimal.
  • So, 0 is the whole number and .6 is the fractional part.
  • The fractional part is added to the integer to make the decimal. 0 + .6 = 0.6.
  • To make it 1, 0.4 must be added, i.e., 0.6 + 0.4 = 1.
  • It is easy to understand now that the decimal number is greater than zero but less than one.
  • Therefore, the decimal 0.6 lies between 0 and 1.
  • Divide the unit length from 0 to 1 into ten equal parts.
  • The sixth position from zero represents the given decimal.

Fractions as Decimals

Fractions can be represented in decimal format by making the denominator 10.

  • For example, 7/2 is the given fraction.
  • The denominator must be 10 to express the fraction in decimal form.
  • So, multiply the denominator by 5. It is a common rule that, if the denominator of a given fraction is multiplied by a number, the numerator must be multiplied by the same number. 
  • Therefore, the fraction becomes, 7×52×5 = 3510 = 3.5.
  • The equivalent of 7/2 is, therefore, 3.5.

Decimals as Fractions

As fractions can be represented as decimals, decimals can also be represented as fractions. The digits right to the decimal point are  to be represented as tenths or powers of tenths after which the improper fraction can be solved.

  • For example, 1.4 is the given decimal number.
  • It can be represented as 1410.
  • By solving the mixed fraction, the fraction 14/10 is obtained.
  • Further simplification of the fraction gives 7/5.
  • Therefore, the fractional form of the decimal 1.4 is 7/5.

Place Value of Decimals

When the place value of decimals is required, only the fractional part is often taken into account. 

  • The immediate right place to the decimal is called the tenths place.
  • The Tenths place denotes 1 unit divided into 10 equal parts.
  • The hundredths place comes after the tenths place.
  • The value of the hundredths place denotes the number of hundredths present there.
  • Following the hundredths place, comes the thousandths and ten-thousandths places, respectively.
  • In the given decimal 6.249, the place value of 2 is in the tenths place, 4 is in the hundredths place, and 9 is in the thousandths place.

Comparing Decimals

When two or more than two decimal numbers have the same whole number, the fractional parts are to be considered to arrange the numbers in order.

  • First, the tenths place must be checked. The number which has a greater number in the tenths place becomes the greater number.
  • If the digits of the tenths place are the same then consider the digits of the hundredths place.
  • Suppose, 45.3, 45.50, 45.56, and 45.8 are the given numbers.
  • The sequence of numbers in increasing order would be 45.3 > 45.50 > 45.56 > 45.8.

Using Decimals

Decimals are used in mathematics as well as in daily life.

  • Suppose, the price of a pencil is 3 rupees and 50 paise.
  • 1 rupee = 100 paise.
  • So, the price of the pencil can be written as 3.5 rupees.

Decimals are used to represent lengths.

  • If someone says, the length of a micro object is 1 mm, it can be said that its length is 0.1 cm. 10mm = 1 cm. Therefore, 1 mm = 1/10 cm = 0.1 cm.
  • Similarly, centimetre can be converted into metre. 1m = 100 cm. Therefore, 1 cm = 1/100 m = 0.01 m.
  • 1000 m = 1 km. Therefore, 1 m = 1/1000 km = 0.001 km.

Decimals can also be used to represent weight.

  • 1000 g = 1 kg. Therefore, 1 g = 1/1000 kg = 0.001 kg.

Addition of Number with Decimals

Addition of whole numbers and addition of decimal numbers follow the same rule. The decimals are to be aligned under one another and the numbers should be arranged according to their place value.

  • Suppose, 2.869 and 5.5 are to be added.
  • The digit 5 of the fractional part is in the tenths place in the number 5.5.
  • So, it must be placed under the digit 8, which is also positioned in the tenths place.
  • Any other arrangement will lead to a faulty result.
  • The sum, therefore, would be 8.369.

Subtraction of Numbers with Decimals

Align the decimals under one another and arrange them according to their place value. Then calculate the difference following the same method as the difference between whole numbers is calculated.

  • For example: subtract 1.1 from 2.31.
  • Place the decimal of the number with a higher value over the decimal of another number, and subtract.
  • 1.21 will be the right answer.

Class 6 Mathematics Chapter 8 Revision Notes – Free Access 

Extramarks understands the importance of making comprehensive notes for the exams. These notes not only make the chapter easy to understand but also help recollect all of the points in less  time. To help students enhance their exam preparation, Extramarks offers Class 6 Mathematics Chapter 8 Notes written by subject matter experts. Students can easily access these notes from the website. 

CBSE Class 6 Mathematics Revision Notes Chapter 8 – Decimals – Introduction

Decimal is a point or dot used in a mathematical expression to represent numerical values. The decimal separates the whole number and the fractional part in a given number, e.g., 3.14. Students can refer to the Class 6 Mathematics Chapter 8 Notes for further clarification.

Tenths And Hundredths in a Decimal

Since 1 m = 100 cm, 1 cm = 1100 m. If the expression is further simplified, 1 cm becomes equivalent to one-hundredth metre or 0.10 cm. Therefore, the first number after the decimal represents the tenth part of the whole.

The method of reading a decimal number includes reading the whole number first, and thereafter reading every digit individually after the decimal. Hence, 15.74 is read as fifteen point seven four.

Class 6 Mathematics Chapter 8 Revision Notes for Representation of Decimals on Number Line

Extramarks’ revision notes on decimals contain a step-by-step explanation of how a decimal number can be represented on the number line. To place a decimal number, one must divide the distance between two numbers on the number line into equal ten parts to represent the tenth part of the number. For example, consider 0.2, 0.6, and 0.9 as given numbers. As these numbers are greater than zero but less than 1 divided the distance between 0 and 1 into ten equal parts. Then, the desired places are marked on the number line.

Benefits Of Revision Notes for Class 6 Mathematics Chapter 8

There are significant benefits of using notes provided by Extramarks. A few of them are given below: 

  • These notes are prepared by a team of subject matter experts.
  • These notes are prepared as per the revised CBSE guidelines.
  • All of the key concepts are extensively covered  in these notes.
  • The notes are prepared in a way to make learning easy and motivate them to  self study.
  • These notes are detailed and lucidly explain every concept with examples.
  • These notes are exclusively made for students to take the load off their mind to provide in-depth understanding of the topic.
  • Students will enjoy Mathematics as a subject, develop confidence to practise more and excel in Mathematics at an early age. .

FAQs (Frequently Asked Questions)

1. What are the important topics covered in the revision notes?

Class 6 Mathematics Chapter 8 Notes focus on the core concepts related to decimals. The list of important topics covered in the notes is given below.

  •  Tenths
  •  Hundredths
  •  Representing decimals on the number line
  •  Fractions as decimals
  • Decimals as fractions
  • Place value of decimals
  •  Comparing decimals
  • Using decimals
  • Addition of a number with decimals
  • Subtraction of a number with decimals

2. What is meant by the decimal notation of a hundredth?

When the distance between two numbers on the number line is divided into hundred equal parts, then each part is called a hundredth.

3. How can you determine the place value of decimals?

The fractional part is considered when the place value of decimals is required. The immediate right place to the decimal is the tenths place, which denotes the tenth part. Then comes the hundredths place followed by the thousandths place. In the given decimal 7.354, the place value of 3 is in the tenths place, 5 is in the hundredths place, and 4 sits in the thousandths place.