Page 8 - TP-Play_V-2.0_Book-8
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The  total  number of  digits used  in a number system is  called  its  base  or  radix.  Therefore,
            when someone says that they are working with number system of radix 2, it means base 2, i.e.,
            binary number system. The base is written after the number as subscript such as (512)10. In this
            example, the number 10 is written as the subscript to express the number in decimal number
            system.

            There are four types of number systems, which are as follows:
            1.  Decimal number system

            2.  Binary number system
            3.  Octal number system

            4.  Hexadecimal number system

            The decimal number system is used in general. However, the computers use binary number
            system. The octal and hexadecimal number systems are also used in the computer.
            Decimal Number System


            The decimal number system is a standard number system for denoting numbers. It consists
            of ten digits from 0 to 9. Only these digits can be used to represent numeric value in decimal
            number system. Hence, the base of decimal number system is 10. The decimal number system is
            the most widely used number system. The value represented by individual digit depends on the
            weight and position of the digit.

            The position of the first digit towards left side of the decimal point is 0. The position of second
            digit towards left side of the decimal point is 1. Similarly, the position of the first digit towards
            right side of decimal point is –1. The position of second digit towards right side of decimal point
            is –2, and so on.

            The value of a number is determined by multiplying the digits with the weight of their position
            and adding the results. This method is known as expansion method. The right-most digit of the
            number has the lowest weight. This digit is called Least Significant Digit (LSD). The left-most
            digit of a number has the highest weight. This digit is called Most Significant Digit (MSD). Digit
            7 in the number 724 is the most significant digit and 4 is the least significant digit.

            The following table shows positional weight of decimal number (724) .
                                                                                    10
                                                     Hundereds             Tens             Units

                    Weights                              10 2               10 1              10 0
                    Real Value of each digit           7 × 10 2          2 × 10  1         4 × 10  0

                    Result                               700                20                 4

            Binary Number System


            The  word  binary  comes  from  'Bi-'  meaning  two.  We  see  'bi-'  in  words  such  as  ‘bicycle‘
            (two wheels) or ‘binocular’ (two eyes). The binary numbers have the base of 2.


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