Free Study Material For RRB Examination: Mathematics (Number System)
Free Study Material For RRB Examination
Subject : Mathematics (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, …}
Rational Numbers: Any number which can be expressed in the form of p/q, where p and q are both integers and q # 0 are called rational numbers.
