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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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