Grade 8 ↓
Number Systems
Introduction
In mathematics, we use different ways to represent numbers and perform operations on them. These different ways of representing numbers are collectively known as number systems. Understanding number systems helps us learn how to work with numbers effectively. In this guide, we will explore the basic concepts, the different types of number systems, and how to convert between them.
What is the number system?
A number system is a way of expressing numbers using a consistent set of symbols and rules. The number system helps in performing mathematical operations such as addition, subtraction, multiplication and division. Different cultures have developed different number systems over time, but the most common and widely used is the decimal system.
Types of number systems
There are many types of number systems, but the four most common are:
- Decimal Number System (Base 10)
- Binary Number System (Base 2)
- Octal number system (base 8)
- Hexadecimal number system (base 16)
Decimal Number System (Base 10)
The decimal number system is the one we use in our daily lives. It is based on ten different digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Each digit has a different place value depending on its place in the number. For example, the number 245 can be expanded as follows:
245 = 2 * 100 + 4 * 10 + 5 * 1
Binary Number System (Base 2)
The binary number system is mainly used in computers and digital systems. It has only two digits, 0 and 1. Each digit in a binary number is called a 'bit'. Binary numbers are important because computers work using the binary system. An example of a binary number is as follows:
The binary number 1011
can be expanded as follows:
1011 (Binary) = 1*2^3 + 0*2^2 + 1*2^1 + 1*2^0 = 8 + 0 + 2 + 1 = 11 (Decimal)
Octal number system (base 8)
The octal number system uses eight digits: 0, 1, 2, 3, 4, 5, 6, and 7. It is sometimes used in computing. An example of an octal number is:
345 (octal) = 3*8^2 + 4*8^1 + 5*8^0 = 192 + 32 + 5 = 229 (decimal)
Hexadecimal number system (base 16)
The hexadecimal number system is used in computing and digital electronics. It uses sixteen unique digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. The letters A through F represent the numbers ten through fifteen. Here's an example of a hexadecimal number:
2F (hexadecimal) = 2*16^1 + 15*16^0 = 32 + 15 = 47 (decimal)
Conversion between number systems
Decimal to binary
To convert a decimal to binary, divide the decimal number by 2 and record the remainder. Keep dividing the quotient by 2 until you reach zero. The binary number is the remainder read from bottom to top. For example, converting 13 to binary:
13 / 2 = 6 remainder 1 6 / 2 = 3 remainder 0 3 / 2 = 1 remainder 1 1 / 2 = 0 remainder 1 Binary: 1101
Binary to decimal
To convert from binary to decimal, multiply each bit by 2, which is the power of its position, counting from right to left, starting at 0. Then sum all the values. For example, converting 1101
to decimal:
1*2^3 + 1*2^2 + 0*2^1 + 1*2^0 = 8 + 4 + 0 + 1 = 13
Decimal to octal
To convert a decimal to octal, divide the decimal number by 8 and record the remainder. Keep dividing the quotient by 8 until you reach zero. The octal number is the remainder read from bottom to top. For example, to convert 65 to octal:
65 / 8 = 8 remainder 1 8 / 8 = 1 remainder 0 1 / 8 = 0 remainder 1 Octal: 101
Octal to decimal
To convert from octal to decimal, multiply each digit by 8, which is the power of its position, counting from right to left, starting at 0. Then sum all the values. For example, to convert 101
to decimal:
1*8^2 + 0*8^1 + 1*8^0 = 64 + 0 + 1 = 65
Decimal to hexadecimal
To convert decimal to hexadecimal, divide the decimal number by 16 and record the remainder. Keep dividing the quotient by 16 until you reach zero. A hexadecimal number is the remainder read from bottom to top. For example, to convert 255 to hexadecimal:
255 / 16 = 15 remainder 15 (f) 15 / 16 = 0 remainder 15 (F) Hexadecimal: FF
Hexadecimal to decimal
To convert hexadecimal to decimal, multiply each digit by its place in the power of 16, counting from right to left, starting at 0. Letter values are used for the digits A through F. For example, converting FF
to decimal:
15*16^1 + 15*16^0 = 240 + 15 = 255
Conclusion
Understanding number systems is important in a variety of fields, especially in computing and digital electronics. Different bases such as binary, octal, and hexadecimal provide simpler ways to handle data on a computer, while the decimal system remains central in everyday arithmetic. Becoming comfortable with conversions between these systems enhances analytical skills and deepens your understanding of the structural similarities and differences between them.