Positional and Non-Positional Number Systems,
In computer science and mathematics, number systems are fundamental for representing numerical values. They are broadly categorized into Positional and Non-Positional Number Systems, each with unique characteristics and applications.
1. Positional Number System
In this system, the position of each
digit relative to others determines its value. The value of a number is
computed based on a base or radix, and each position represents a power of the
base.
Key Characteristics:
- Base/ Radix:
The number of distinct digits used, including 0. For example:
- Binary (Base 2): Uses digits 0 and 1.
- Decimal (Base 10): Uses digits 0 through 9.
- Hexadecimal (Base 16): Uses digits 0-9 and letters
A-F.
- Positional Weight:
Each digit’s value is multiplied by the base raised to the power of its
position. For instance, in decimal 432=4×102+3×101+2×100432 = 4 \times
10^2 + 3 \times 10^1 + 2 \times 10^0432=4×102+3×101+2×100.
- Examples in Computing:
- Binary is used in computer architecture.
- Octal and hexadecimal simplify binary representation
for humans.
Advantages:
- Efficient for performing arithmetic operations.
- Compact and scalable for large numbers.
Examples:
- Binary:
10112=1×23+0×22+1×21+1×20=11101011_2 = 1 \times 2^3 + 0 \times 2^2 + 1
\times 2^1 + 1 \times 2^0 = 11_{10}10112=1×23+0×22+1×21+1×20=1110
- Decimal:
342.5=3×102+4×101+2×100+5×10−1342.5 = 3 \times 10^2 + 4 \times 10^1 + 2
\times 10^0 + 5 \times 10^{-1}342.5=3×102+4×101+2×100+5×10−1
2. Non-Positional Number System
In this system, the position of a
digit does not affect its value. Each symbol represents a fixed value, and the
overall value is determined by simple addition.
Key Characteristics:
- No base or positional weight.
- Limited arithmetic utility; primarily used in
historical or specific contexts.
Examples:
- Roman Numerals:
XII=10+1+1=12XII = 10 + 1 + 1 = 12XII=10+1+1=12
- Egyptian Numerals:
Based on symbols for 1, 10, 100, etc., where repetition indicates
addition.
Applications:
- Historical and cultural significance.
- Limited modern use except in clocks, book chapters,
etc.
Advantages:
- Simple representation for small numbers.
- Easy to learn and use for basic counting.
Comparison:
Feature |
Positional
System |
Non-Positional
System |
Base/ Radix |
Required (e.g., 2, 10, 16) |
Not required |
Positional Weight |
Present |
Absent |
Arithmetic Utility |
Highly efficient |
Limited |
Examples |
Binary, Decimal, Hexadecimal |
Roman Numerals, Tally Marks |
Application in Computers |
Universally used |
Rarely used |
Importance in Computers:
- Positional Number Systems are essential for digital systems:
- Binary underpins machine-level operations.
- Hexadecimal simplifies memory addressing and
debugging.
- Non-Positional systems have no practical computational
application but offer educational insights into the evolution of numerical
representation.
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