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Number System

The base-9 number system, also called the nonary system, is a positional numeral system that uses nine digits: 0, 1, 2, 3, 4, 5, 6, 7, and 8. Each digit’s position represents a power of 9, starting from $9^0$ at the rightmost digit and increasing to the left. For example, the base-9 number 357 represents $3 \times 9^2 + 5 \times 9^1 + 7 \times 9^0 = 243 + 45 + 7 = 295$ in decimal. Base-9 is useful in mathematics for exploring alternative numeral systems, positional notation, and patterns in numbers. While it is not commonly used in everyday applications or computing, it provides a unique perspective on arithmetic operations, divisibility, and number representation beyond the decimal system. Studying base-9 helps learners understand how positional systems work, how numbers can be converted between bases, and how different bases affect fraction representation and arithmetic properties. It is also valuable in theoretical mathematics and educational exercises, allowing students to develop logical thinking and problem-solving skills. Understanding the nonary system enriches knowledge of number systems and provides a foundation for exploring higher-level mathematics, coding theory, and abstract numeral systems.

Number System

The octal number system, also known as base-8, is a positional numeral system that uses eight digits: 0, 1, 2, 3, 4, 5, 6, and 7. Each digit represents a power of 8, with the rightmost digit representing $8^0$, the next representing $8^1$, and so on. For example, the octal number 157 equals $1 \times 8^2 + 5 \times 8^1 + 7 \times 8^0 = 64 + 40 + 7 = 111$ in decimal. Octal was widely used in early computing systems because it provides a more compact representation of binary numbers: each octal digit corresponds exactly to three binary digits. This makes conversion between binary and octal straightforward and simplifies programming and memory addressing in older computer architectures. Although modern systems primarily use hexadecimal (base-16), octal remains important in some computing contexts, such as Unix file permissions, digital electronics, and certain embedded systems. Understanding octal helps in grasping how different number bases can efficiently represent information and interact with binary systems. It also provides a foundation for learning hexadecimal and other positional numeral systems used in digital technology.