Numeral/Numerical/Number Systems/Representations/Notations
  • is a writing system for expressing numbers (mapping numbers to characters)
  • i.e. it defines how we represent an abstract number into a sequence of symbols/characters, and where the number of distinct symbols allowed is fixed
  • e.g. the abstract number twelve is represented as a sequence of symbols 12 (1 followed by 2). The number of distinct symbols used in this numeral system is ten (i.e. 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9)
  • similar to the character set, but different

Numeral/Number Systems/Representations/Notations - Types

Type

Alias

# of Distinct Symbols

Symbols Commonly Used

Base64 Notation

64

a subset of ASCII characters

Base64url Notation

64

a variant of Base64 Notation used in URLs

Base60

Sexagesimal

60

originated with ancient Sumerians in the 3rd millennium BC, and was passed down to the Babylonians

Base32 Notation

32

Base16

Hexadecimal

16

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Base12

Duodecimal

12

Base10

Decimal

10

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Base8

Octal

8

Base4 Notation

Quaternary

4

Base2

Binary

2

0, 1

Base1

Unary

Tally Marks

1

1

Roman Numerals

N/A

𝐼, 𝑉, 𝑋, 𝐿, 𝐶, 𝐷, 𝑀, 𝑉̅, 𝑋̅, 𝐿̅, 𝐶̅, 𝐷̅, 𝑀̅, etc

Scientific Notation

Residue Number System (RMS) - Complete Residue System - Reduced Residue System