Numeral systems by culture | |
---|---|
Hindu-Arabic numerals | |
Western Arabic (Hindu numerals) Eastern Arabic Indian family Tamil |
Burmese Khmer Lao Mongolian Thai |
East Asian numerals | |
Chinese Japanese Suzhou |
Korean Vietnamese Counting rods |
Alphabetic numerals | |
Abjad Armenian Āryabhaṭa Cyrillic |
Ge'ez Greek Georgian Hebrew |
other historical systems | |
Aegean Attic Babylonian Brahmi Egyptian Etruscan Inuit |
Kharosthi Mayan Quipu Roman |
Positional systems by base | |
Decimal (10) | |
2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 20, 24, 27, 30, 36, 60, 64 | |
Balanced ternary | |
Non-positional system | |
Unary numeral system (Base 1) | |
List of numeral systems | |
This is a list of numeral systems.
Contents |
These numeral systems use place-value notation.
For the definition of standard positional numeral systems, see Non-standard positional numeral systems.
The common names are derived somewhat arbitrarily from Latin and Greek. For more information, see Hexadecimal#Etymology.
Base | Name | Usage |
---|---|---|
2 | Binary | All modern digital computations. |
3 | Ternary | Cantor set (all points in [0,1] that can be represented in ternary with no 1s.) |
4 | Quaternary | Data transmission and Hilbert curves. |
5 | Quinary | |
6 | Senary | Diceware |
7 | Septenary | |
8 | Octal | Charles XII of Sweden, Unix-like permissions |
9 | Nonary | |
10 | Decimal | Most widely used by modern civilizations.[1][2] |
11 | Undecimal | |
12 | Duodecimal | |
13 | Tridecimal | The Maya calendar. |
14 | Tetradecimal | Programming for the HP 9100A/B calculator[3] and image processing applications[4]. |
15 | Pentadecimal | Telephony routing over IP and the Huli language. |
16 | Hexadecimal | Human-friendly representation (hex dump) of binary data and Base16 encoding. |
20 | Vigesimal | Celtic numerals, Maya numerals |
24 | Tetravigesimal | |
26 | Hexavigesimal | |
27 | Septemvigesimal | Telefol and Oksapmin languages. |
30 | Trigesimal | |
32 | Duotrigesimal | Base32 encoding and the Ngiti language. |
36 | Hexatridecimal | Base36 encoding. |
60 | Sexagesimal | The Babylonian numerals positional numeral system. |
64 | Tetrasexagesimal | Base64 encoding. |
85 | Ascii85 encoding. |
Base | Name | Usage |
---|---|---|
1 | Unary | Tally marks. |
10 | Decimal without a zero |
Base | Name | Usage |
---|---|---|
2 | Non-adjacent form | |
3 | Balanced ternary | Ternary computers. |
The common names of the negative base numeral systems are formed using the prefix nega-, giving names such as:
Base | Name | Usage |
---|---|---|
−2 | Negabinary | |
−3 | Negaternary | |
−10 | Negadecimal |
Base | Name | Usage |
---|---|---|
2i | Quater-imaginary base | |
−1 ± i | Twindragon base | Twindragon fractal shape. |
Base | Name | Usage |
---|---|---|
φ | Golden ratio base | Early Beta encoder.[5] |
e | Base e | |
π | Base π | |
√2 | Base √2 |
All known numeral systems developed before the Babylonian numerals are non-positional.
Name | Base | Sample | Approx. first appearance |
---|---|---|---|
Babylonian numerals | 60 | ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
3100 B.C. |
Greek numerals | 10 | α β γ δ ε ϝ ζ η θ ι | |
Roman numerals | 10 | I II III IV V VI VII VIII IX X | 1000 B.C. |
Chinese rod numerals | 10 | ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
1st century |
Arabic numerals | 10 | 0 1 2 3 4 5 6 7 8 9 10 | 9th century |
Helena Petrovna Blavatsky (Russian: Еле́на Петро́вна Блава́тская, Yelena Petrovna Blavatskaya; 12 August [O.S. 31 July] 1831 – 8 May 1891) was an occultist, spirit medium, and author who co-founded the Theosophical Society in 1875. She gained an international following as the leading theoretician of Theosophy, the esoteric movement that the Society promoted.
Born into an aristocratic Russian-German family in Yekaterinoslav, Blavatsky traveled widely around the Russian Empire as a child. Largely self-educated, she developed an interest in Western esotericism during her teenage years. According to her later claims, in 1849 she embarked on a series of world travels, visiting Europe, the Americas, and India. She alleged that during this period she encountered a group of spiritual adepts, the "Masters of the Ancient Wisdom", who sent her to Shigatse, Tibet, where they trained her to develop her own psychic powers. Both contemporary critics and later biographers have argued that some or all of these foreign visits were fictitious, and that she spent this period in Europe. By the early 1870s, Blavatsky was involved in the Spiritualist movement; although defending the genuine existence of Spiritualist phenomena, she argued against the mainstream Spiritualist idea that the entities contacted were the spirits of the dead. Relocating to the United States in 1873, she befriended Henry Steel Olcott and rose to public attention as a spirit medium, attention that included public accusations of fraudulence. One of her sources of inspiration was a book by Emil Schlagintweit, Le Bouddhisme Au Tibet, published in 1881.
The Septenary in Helena Blavatsky's teachings refers to the seven principles of man. In The Key to Theosophy she presents a synthesis of Eastern (Advaita Vedanta, Samkhya) and Western (Platonism, 19th century Occultism) ideas, according to which human nature consists of seven principles. These are:
Each of these principles are embodied as such: