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There are four types of number systems which are as follows:

                      1.  Decimal number system                              3.  Octal number system
                      2.  Binary 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 any 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 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 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). The
                  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. You see 'bi-' in words such as ‘bicycle‘ (two
                  wheels) or ‘binocular’ (two eyes). The binary numbers have the base of 2.
                   Clickipedia


                    A single binary digit (like '0' or ‘1’) is called a ‘bit’. For example 11010 is five bits long. The word bit

                    is made up from the words 'binary digit’.


                  A computer is a machine made up of transistors, switches and other components. All these
                  electronic components are in two mutually exclusive states, either ON or OFF. The two binary
                  digits represent these two states. Every instruction given to a computer is converted into 0’s and
                  1’s so that it can be understood and implemented by the computer. Binary language is therefore
                  known as the machine language.



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