# NCERT Solutions for Class 6 Maths Chapter 1 Exercise 1.1

NCERT Solutions for Class 6 Maths Chapter 1 Exercise 1.1 (Ex. 1.1) Knowing Our Numbers in PDF file format free to use in Hindi Medium as well as English Medium. Additional questions with answers are also given for practice.

All the contents are updated for academic session 2020-2021 for CBSE and state board students. Videos solutions are also available to use online free or download.

## Class 6 Maths Chapter 1 Exercise 1.1 Solutions

Class: 6 | Mathematics |

Chapter: 1 | Knowing Our Numbers |

Exercise: 1.1 | NCERT Solutions |

### CBSE NCERT Class 6 Maths Exercise 1.1 Solutions in Hindi and English Medium

### Class 6 Maths Exercise 1.1 Solution in Video

### More about Class 6 Maths Exercise 1.1

In earlier classes, we have studied numbers, small as well as large. We have studied the four basic operations on these numbers. We have studied about patterns in number sequences and done many other interesting things with the numbers. In this chapter, we shall study such interesting things with a bit of review and revision as well.

#### Know about Natural Numbers

We use numbers 1, 2, 3, 4 … to count and calculate. Therefore, these numbers are called Counting Numbers. However, we also use the name natural numbers for counting numbers. Thus, 1, 2, 3…, 10…, 80… 1005 … are all natural numbers.

Since we start counting with the number 1, therefore, 1 is the first or the smallest natural number. The next number is 2 which is obtained by adding 1 to the first natural number. By adding 1 to 2, we get 3, the third natural number. In fact, by adding 1 to a natural number, we get the next natural number. Thus, 30 (= 29 + 1) is the natural number next to 29.

##### What ar Whole Numbers?

In order to describe the number of elements in a collection with no objects, we use the symbol ‘0’ called zero. The number ‘0’ together with the natural numbers gives us the numbers 0, 1, 2, 3, 4 … which are called whole numbers.

- Digits: In order to represent any number, we use ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. These ten symbols are called digits or figures.
- Numeral: A group of digits denoting a number is called a numeral.

For example, 5467, 20346, 945860 etc. are numerals. - Notation: The method of representing a number in digits or figures is called notation.
- Numeration: The method of expressing a number in words is called numeration.

###### Methods of Numeration

There are two commonly used methods of numeration:

(i). Indian System of Numeration

(ii) International System of Numeration

In Indian system, a number is split up into groups or periods starting from the right. The groups are called ones, thousands, lakhs, crores and arabs. The ones in turn are split into hundreds, tens and units.

Generally, we separate the periods by marking commas (,). In the modern notation, we leave a short space between the periods, instead of using a comma. Thus, 468572309 is written as 46,85,72,309 or 46 85 72 309. It is read as forty-six crore eighty-five lakh seventy-two thousand three hundred nine.

This number represents a collection of 46 crores, 85 lakhs, 72 thousands, 3 hundreds and 9 ones. Therefore, we can write it in expanded form as under: 46,85,72,309 = 4 × 100000000 + 6 × 10000000 + 8 × 1000000 + 5 × 100000 + 7 × 10000 + 2 × 1000 + 3 × 100 + 0 × 10 + 9 × 1.

###### International System of Numeration

The International System of Numeration is being followed by most of the countries of the world. In this

system also, a number is split up into groups or periods. Starting from the right, the groups are called

ones, thousands, millions and billions. The ones in turn are split into hundreds, tens and ones.

##### How many natural numbers can be there?

If we start counting 1, 2, 3… 8, 9… 100… 190, 191… 300 … and continue to count, there would be no end. Even if we continue to count day and night for our whole life; still we cannot reach end. In other words, we cannot complete the counting of natural numbers. Obviously, there is no last or the greatest natural number.

##### What is the difference of the place values of two 5’s in 86542359?

The 5 in the second place from the right is at ten’s place.

So, place value of 5 in ten’s place = 50.

The second 5 is in the 6th place from the right.

So, it is at lakh’s place.

So, Place value of other 5 = 500000.

Hence, required difference = 500000 – 50 = 499950.

##### How many 6-digit numbers are there in all?

The largest 6-digit number = 999999

The smallest 6-digit numbers = 100000

Number of all 6-digit numbers = (999999 – 100000) + 1

= 899999 + 1 = 900000.

Hence, the number of all 6-digit numbers is nine lakhs.