NCERT Solutions for Class 6 Maths Chapter 1 Exercise 1.1

Class VI Mathematics NCERT Book Ex. 1.1 of chapter 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 CBSE session 2024-25 for state board students also. Videos solutions are also available to use online free or download.

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.

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.

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.

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.

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.