(Guidance Programme) Combined Higher Secondary Level [CHSL] (10+2) Exam : Number System

In Indian system, numbers are expressed by means of symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, called digits. Here, 0 is called insignificant digit whereas 1, 2, 3, 4, 5, 6, 7, 8, 9 are called significant digits. We can express a number in two ways.

Notation: Representing a number in figures is known as notation as 350.

Numeration: Representing a number in words is known as numeration as ‘Five hundred and forty five’.

Face Value and Place Value of a Digit
Face Value: It is the value of the digit itself eg, in 3452, face value of 4 is ‘four’, face value of 2 is ‘two’.
Place Value: It is the face value of the digit multiplied by the place value at which it is situated eg, in 2586, place value of 5 is 5 × 102 = 500.
Number Categories
Natural Numbers (N): If N is the set of natural numbers, then we write N = {1, 2, 3, 4, 5, 6,…}
The smallest natural number is 1.
Whole Numbers (W): If W is the set of whole numbers, then we write W = {0, 1, 2, 3, 4, 5,…}
The smallest whole number is 0.
Integers (I): If I is the set of integers, then we write I = {– 3, –2, –1, 0, 1, 2, 3, …}

SSC CHSL (10+2) Exam : Printed Study Materials

SSC CGL Tier-1 Exam Printed Study Materials