Page 26 - Maths Class 06

2. In each of the follow ing pairs of the numbers, state which whole number is on the left of the other
number on the number line:
(a) 2221 and 2251
(b) 9521 and 5921

(c) largest 2 digit number and smallest three digit number.
3. Add 5 and 6 using the number line.
4. Multiply 5 by 3 using the number line.
5. Using number line, find the following:

(a) 4 + 3 (b) 5 + 6 + 1 (c) 5 - 4 (d) 2 ´ 4

Properties of Whole Numbers

Let us discuss few properties of whole numbers involving basic operations like addition, subtraction,
multiplication and division.
I. Addition Properties

Property 1.

Closure Property : If a and b are two whole numbers and a b+ = c, then result c is also a whole number.
For example, (i) 3 + 4 = 7, which is a whole number.
(ii) 25 25+ = 50, which is a whole number.

(iii) 100 + 125 = 225, which is a whole number.
Property 2.

Commutative Law of Addition : If a and b are any two whole numbers, then a b+ = b a+ .
For example, (i) 3 5+ = 8 and 5 3+ = 8

Hence, 3 5+ = 5 3+ .
(ii) 20 + 30 = 50 and 30 + 20 = 50
Hence, 20 + 30 = 30 + 20.

(iii) 150 + 250 = 400 and 250 + 150 = 400
Hence, 150 + 250 = 250 + 150.

Property 3.
Additive Property of Zero : If a is any whole number, then a + 0 = 0 + a = a

Hence, the sum of any whole number and 0 is the number itself. 0 is called the identity for addition.
For example, (i) 5 0+ = 0 + 5 = 5
(ii) 28 0+ = 0 + 28 = 28

(iii) 123 0+ = 0 + 123 = 123
Property 4.

Associative Law of Addition : If a b, and c are three whole numbers, then
a
(a b+ ) c+ = + (b c+ )

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