# Knowing our Numbers

## An Overview of Chapter 1 - Knowing Our Numbers

Knowing about numbers is necessary for solving mathematical equations. You have already learnt how to deal with the numbers and their basic operations. Moreover, you already know addition, subtraction, division, and multiplication.

Furthermore, in the first chapter of class six, knowing our numbers, you will learn a series of new topics along with little revision. These topics include –

• Patterns in number.

• Indian arrangement of numeration.

• Universal arrangement of numeration.

• Estimation.

• Comparing numbers, finding the greatest and smallest numbers.

• Learning large numbers up to 1 crore.

Knowing our numbers class 6 exercise 1.1 is the introduction section. Read on to know about other chapters.

Knowing Our Numbers Class 6 Exercise 1.2

The knowing our numbers class 6 exercise 1.2 is comparing numbers.

In this section, you will learn to compare between various numbers and then determine the biggest or smallest value. For example, determine the biggest number form the following questions:

1. 42, 96, 33, 102

2. 4420, 2520, 9656, 8448

Let’s take a look at an example to get a better understanding. There are two numbers 2230 and 5412, now to compare these two numbers, consider their digits at the thousands place.

Here, 5 in 5412 is greater than 2 in 2230. Thus, 5412 is higher than 2230.

Additionally, there are two numbers, 7787 and 7841. However, these two numbers have the same digit in their thousands place. Hence, you need to move to the next digit, i.e. hundreds place to determine the highest number. Therefore, between 7 in 7787 and 8 in 7841, the latter is the greater one which makes 7841 is the bigger number.

This chapter is further divided into other sections dealing with a particular topic.

1.2.1 How Many Numbers Can You Make?

In this section of knowing our numbers class 6, you will learn to make numbers from various digits. Moreover, there are special instructions, like not using one particular digit twice, etc.

1.2.2 Shifting Digits

Here you can learn how to have some fun with numbers by interchanging the positions of different digits. For instance, you have 6547, and now if you switch the position of first and last digit, you will get 7546. Therefore, this new number is higher than the former one.

1.2.3 Introducing 10,000

In your previous chapters, you have learnt that beyond 99 it becomes a three-digit number and beyond 999 there are four-digit numbers. Now, if you move on after 9999, it becomes a five-digit number. Therefore, if you do 9999+1, you will get 10,000.

1.2.4 Revisiting The Place Value

You have already learnt the method to expand numbers. In this section of knowing our numbers exercise 1.2, you get a chance to revise this concept once again. Example: 55= 50+5 = 5X10+5.

1.2.5 Introducing 1,00,000

Adding one to the highest five-digit number, i.e. 99,999 will result in 1,00,000. In this section of NCERT class 6 knowing our numbers, you can learn more about five-digit numbers.

1.2.6 Larger Numbers

Here you can learn more about seven and eight-digit numbers. Moreover, you will also prepare all the knowing our numbers class 6 extra questions related to large numbers at the end of this chapter for revision.

1.2.7 An Aid in Reading and Writing Large Numbers

However, managing these big numbers is not an easy task. They are difficult to calculate and remember. Therefore, to simplify this process, indicators like commas are used. You have already noticed the use of commas and used it to write such big numbers.

Indian numeration system, commas are used to mark thousands, lakhs and crores. You can also learn about the international numeration system here.

Additionally, the first section of knowing our numbers class 6 exercise 1.3 aids you to understand the units of measurement, and you get to learn the usability of such measurement units.

For instance, if you are calculating the height of a pen, you can use centimetre. However, if you are calculating the distance between Chennai and Mumbai, then it will be easier to use a higher unit of length, like kilometre.

1.3.1 Estimation

In this section, you get a chance to learn in great detail about estimation. Every aspect of estimation has been discussed here, and gradually you move to higher calculations.

1.4 Using Brackets

The use of brackets can help you to avoid unnecessary confusion during your calculations. Under this section of knowing our numbers, you can learn different usage of brackets.

1.5 Roman Numerals

Last but not least, this section of this first chapter will help you gain an understanding of roman numerals.

Vedantu- Your Partner for Better Preparation

Knowing our numbers is one of the most crucial chapters of class 6 mathematics. This chapter is the stepping stone of class six mathematics syllabus. Moreover, students can download the Vedantu app to join the live classes. Subject experts from across the country conduct these classes. They can learn new techniques and clear their doubts as well.

Students willing to learn more about other chapters of class six mathematics can visit the official website of Vedantu. Additionally, they can download the NCERT solutions for class 6 maths chapter 1 knowing our numbers from the official website of Vedantu.

1. What is estimation in mathematics? How to round off numbers?

Ans. Estimation in mathematics is making an assumption or rounding off a particular number for better understanding and quick calculation. For instance, 25,158 people have attended a recent football match. However, for better reference, this number is rounded-off to its nearest round number, i.e. either 25,000 or 25,500.

On the other hand, referring 25,128 as 26,000 is not a correct estimation. Additionally, to round off numbers using this method, you can take help of the estimation and use the nearest estimated number. You can use this estimation method to perform mathematical operations as well. Moreover, this method helps in quick calculation and representing an exact figure that is often difficult to calculate.

2. Which is the lowest five-digit number?

Ans. 10, 000 is the smallest five-digit number. Moreover, it appears by adding 1 with the highest four-digit number, i.e. 9,999. The pattern followed for this calculation is, 9+1=10=10X1; 99+1=100=100X1; 999+1=1000=1000X1; 9,999+1=10,000=10,000X1.

Furthermore, you can use this method to calculate an even larger number with six, seven-digits. This process further explains that, highest single-digit number + 1 = smallest two-digit number; greatest two-digit number + 1 = smallest three-digit number; highest three-digit number + 1 =  smallest four-digit number, and so on.

3. What is the International System of Numeration?

Ans. Similar to the Indian system of numeration, there is an International system of numeration. However, unlike the Indian system, here commas mark thousands and millions. One million is equal to a thousand thousands.

Moreover, in this system, commas come after every three-digit from the right. Here the first one marks thousand and the next one is for millions. For instance, 45,520,598 is read as forty-five million five hundred twenty thousand five hundred and ninety-eight according to the international system. On the other hand, in the Indian system, it will be read as four crores fifty-five lakhs twenty thousand five hundred and ninety-eight.

Additionally, in the international system, billion is used to denote any number larger than millions. Thus, 1 billion = 1000 million.

4. What is the purpose of a comma?

Ans. Commas play a pivotal role in writing, learning and remembering large numbers. The Indian System of Numeration uses ones, tens, thousands, lakhs and then crores. Commas help in marking these. Moreover, in the Indian system commas are used in indicating thousands, lakhs, and then crores.

Furthermore, the initial comma comes after hundreds place, i.e. three digits from the right. After that, the second comma comes after two digits, which marks lakh. Finally, the third comma comes after another two digits, i.e. seven digits from the right. Thus, it marks crore.