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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 a 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) . In this example,
10
the number 10 is written as the subscript to express the number in the decimal number system.

WHY COMPUTERS USE NUMBERS?

Computers use numbers because they process information in a binary format, which consists of
only two numbers: 0 and 1. These binary digits or "bits," represent electrical signals that can either
be off (0) or on (1). All types of data—whether text, images or sound—are converted into numbers,
specifically binary code, so that computers can store, process and manipulate them efficiently.

Factbot

The numerical digits, we use today, i.e., 1, 2 and 3 are based on the Hindu-Arabic numeral system.
Different names for the number 0 include zero, nought, naught, nil, zilch and zip.

TYPES OF NUMBER SYSTEMS

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

Experiential Learning Lab Activity

Find out more about the numeral system in different states of India. Write it in your notebook and type it
in a Word document as well.

Decimal Number System

The decimal number system is a standard for denoting numbers. It consists of ten digits ranging from 0
to 9. Only these digits can be used to represent a numeric value in the decimal number system. Hence,
the base of the decimal number system is 10. The decimal number system is the most commonly used.
The value represented by an individual digit depends on the weight and position of the digit.
The first digit's position to the left of the decimal point is considered 0. The second digit's position to the
left of the decimal point is considered 1 and so on. The first digit's position to the right of the decimal
point is considered -1. The second digit's position to the right of the decimal point is considered -2, and
so on.

In a decimal number system, each digit's value is determined by multiplying the digit itself by the weight
of its position within the number, and then summing up the results. This method is known as the
expansion method. The right-most digit of the number has the lowest weight. This digit is called the
Least Significant Digit (LSD). The number's left-most digit has the highest weight.

Number Systems & Binary in Computing and AI 69