[Maths Class Notes] on Knowing our Numbers Pdf for Exam

Knowing our Numbers is the first chapter in NCERT for the 6th class. It is very important to go through this chapter thoroughly as it would create a foundation for students for the further chapters in the book. The topics that are discussed in this chapter are listed below-

Introduction

The first section is the introduction which introduces the importance of numbers that help us to count or arrange the objects and are used in many different contexts. These are arithmetic values that help us to convey the magnitude of all the objects that are present around us.

Comparing Numbers

In order to understand mathematical concepts such as greater than or equal to, the comparison of numbers is important. The subtopics of comparing numbers are:

How many numbers can you make?

In this part, students will learn how they can make numbers from given digits. Numbers will be formed in such a way that no digit is repeated in a single number and there cannot be two exact numbers. Students will also learn about the different orders of numbers which are ascending (smallest to greatest) and descending (greatest to smallest).

Shifting digits

In this part, students will learn how a small shift in the digits of the numbers can make a difference in the value of the number.

Introducing 10,000

In this part, students learn about the greatest 3-digit number which is 999, and what happens when we add a 1 to 999.

Revisiting place value

In this part, students will learn about the expansion of 2-digit, 3-digit, and 4-digit numbers and the place value for each digit.

Introducing 1,00,000

In this part, students will learn about the greatest 5-digit number which is 99999, and what happens when 1 is added to 99999.

Larger Numbers

In this section, students will learn about the greatest and smallest 6-digit, 7-digit, and 8-digit numbers which include numbers like 10 lakh and one crore.

An aid in reading and writing large numbers

This section will explain to the students how to read and write large numbers by identifying the digits in one place, tens place, hundreds place, and so on.

Use of commas

This chapter will also help the students to learn the use and importance of commas in the number system.

Large Numbers in practice

Students will learn about large numbers and how they can be written in shorter forms by using units such as centimeters and meters, grams and kilograms, meters and kilometers, etc.

Estimation

This section will help the students to learn about the approximate or near values of certain numbers. Let us have a look at the subsections.

Estimating the nearest tens by rounding off

In this section, students will learn how to round off numbers to the nearest tens. Suppose 13 is a number that lies between 10 and 20, but since it is closer to 10, therefore it would be rounded off to the nearest tens which are 10.

Estimating the nearest hundreds by rounding off

Here students will learn how to round off numbers to the nearest hundreds, for example, 310 lies between 300 and 400 but are closer to 300, therefore it will be rounded off to 300.

Estimating the nearest thousands by rounding off

Just like nearest tens and hundreds, students will also learn about how to round off numbers to the nearest thousand. For example, 8600 is a number that lies between 8000 and 9000 but since it is closer to 9000, it would be rounded off to the nearest thousand which is 9000.

Estimating outcomes of number situations

Students will learn about the situations where we need to answer quickly for how to add numbers quickly by keeping the digits of the numbers being added in the same place and rounding them off to the nearest values.

To estimate sum or difference

It is not always necessary that you need to round off, therefore in this section students will learn why and when we need to round off.

To estimate products

Here the students will learn about the general rule which states that estimating while multiplying can be done by rounding off each factor to its greatest place and then multiplying those factors. 

Using brackets

Students will learn about the use of brackets and how they are used in order to avoid confusion while doing mathematical calculations. In expanding brackets the students will learn the systematic procedure for the removal of brackets.

Roman Numerals

Students will study one of the earliest systems which are roman numerals and are still used in many places