PARAGON CONVENT SCHOOL SECTOR 24 B CHANDIGARH CLASS

PARAGON CONVENT SCHOOL SECTOR – 24 B, CHANDIGARH

CLASS - 7 CH – 4 ( RATIONAL NUMBERS)

Rational number A number that can be expressed as a/b is a rational no if a and b are integers and b is not equal to o. Ex : 5 , 7 , 3 , 0 9 10 5 1

PROPERTIES OF RATIONAL NUMBERS 1. Every natural number is a rational number. For example 5 is a natural no which can be written as 5 , thus making it a rational no as well. 1 2. Every whole no is a rational no. 3. Every integer is also a rational no 4. Every fraction is also a rational no. 5. Division by 0 is not allowed, so a rational no cannot have 0 in the denominator.

Rational no on a number line • Represent 2 , 1 , 0 , - 3 on a number line Sol : -3 -2 4 4 4 -1 4 0 4 4 1 4 2 4 3 4

Standard form of a rational no • A rational no is said to be in standard form if and only if – • The numerator and denominator are co-prime • The denominator of the rational no is positive Ex : convert 10/15 in standard form. 10 ÷ 5 = 2 15 ÷ 5 3

Comparison of rational numbers • Ex : compare 4 and 5 4 x 2=8 5 x 1 = 5 so 8 > 5 Hence 4 > 1 5 2 1 2

Absolute value of a rational number • The absolute value of a rational number is greater than or equal to that number itself. • Ex : find the absolute value of -4 7 Absolute value = -4 = 4 7 7