Number Systems - Revision Notes
CBSE Class 09 Mathematics Revision Notes CHAPTER – 1 NUMBER SYSTEMS 1 Rational Numbers 2 Irrational Numbers 3 Real Numbers and their Decimal Expansions 4 Operations on Real Numbers 5 Laws of Exponents for Real Numbers Natural numbers are : 1, 2, 3, …………….. denoted by N. Whole numbers are : 0, 1, 2, 3, ……………… denoted by W. Integers : ……. -3, -2, -1, 0, 1, 2, 3, ……………… denoted by Z. Rational numbers - All the numbers which can be written in the form p q p q are called rational numbers where p and q are integers and q ≠ 0. q ≠ 0. Every integer p is also a rational number, can be written as p 1 . p 1 . Irrational numbers - A number is called irrational, if it cannot be written in the form p q p q where p and q are integers and q ≠ 0. q ≠ 0. The decimal expansion of a rational number is either terminating or non terminating recurring. Thus we say that a number whose decimal expansion is either terminating or non...