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Greek numerals are a system of representing numbers using letters of the Greek alphabet. In modern Greece, they are still in use for ordinal numbers, and in much the same situations as Roman numerals are in the West; for ordinary numbers, arabic numerals are used.
The earliest system of numerals in Greek was acrophonic, operating much like Roman numerals, with the following scheme: Ι = 1, Π = 5, Δ = 10, Η = 100, Χ = 1000, and Μ = 10000.
Starting in the 4th century BC, the acrophonic system was replaced with a quasi-decimal alphabetic system, sometimes called the Ionic numeral system. Each unit (1, 2, ..., 9) was assigned a separate letter, each tens (10, 20, ..., 90) a separate letter, and each hundreds (100, 200, ..., 900) a separate letter. This requires 27 letters, so the 24-letter Greek alphabet was extended by using three obsolete letters: digamma (Ϝ, also used are ς or στ) for 6, qoppa (Ϟ) for 90, and sampi (Ϡ) for 900. An acute sign (´) is used to distinguish numerals from letters.
The alphabetic system operates on the additive principle in which the numeric values of the letters are added together to form the total. For example, 241 is represented as σμα´ (200 + 40 + 1).
To represent numbers from 1,000 to 999,999 the same letters are reused to serve as thousands, tens of thousands, and hundreds of thousands. A comma or inverted acute is put in front of thousands to distinguish them from the standard use. For example, 2004 is represented as ,βδ´ (2000 + 4).
| Letter | Value | Letter | Value | Letter | Value |
|---|---|---|---|---|---|
| α´ | 1 | ι´ | 10 | ρ´ | 100 |
| β´ | 2 | κ´ | 2020 twenty is the natural number following 19 and preceding 21. Cardinaltwenty Ordinaltwentieth Numeral system vigesimal Factorization Roman numeralXX Binary10100 Hexadecimal14 In mathematics Twenty is a composite number, its proper divisors being 1, 2, 4, | σ´ | 200Integers 200 is the natural number following 199 and preceding 201. CardinalTwo hundred Ordinal200th Factorization Roman numeralCC Binary11001000 HexadecimalC8 Two hundred is the smallest unprimeable number it can not be turned into a prime number by chan |
| γ´ | 33 three is the natural number following 2 and preceding 4. Prefixes for 3 include tri- ( Greek) and tre- Latin. Evolution of the glyph Three is often the largest number written with as many lines as the number represents. Even the Romans tired of writing | λ´ | 3030 thirty is the natural number following 29 and preceding 31. Cardinalthirty Ordinalthirtieth Numeral system Factorization Divisors2, 3, 5, 6, 10, 15 Roman numeralXXX Binary11110 Hexadecimal1E In mathematics It is a primorial as well as the sum of the sq | τ´ | 30039e02 300 Three hundred is the natural number following two hundred ninety-nine and preceding three hundred one. CardinalThree hundred Ordinal300th Factorization Roman numeralCCC Binary100101100 Hexadecimal12C Mathematical Properties It is a triangular nu |
| δ´ | 4This article discusses the number Four . Four is also the name of a French commune, Four, Isere. 4 four is the natural number following 3 and preceding 5. Prefixes for 4 include tetra- ( Greek) and quad- ( Latin). Evolution of the glyph Representing 1, 2 | μ´ | 40Integers Composite numbers 40 is the natural number following 39 and preceding 41. In English, forty is the only number whose constituent letters appear in alphabetical order. Cardinal forty Ordinal40th (fortieth) Numeral system Factorization Divisors 2, | υ´ | 40049e02 400 Four hundred is the natural number following three hundred ninety-nine and preceding four hundred one. CardinalFour hundred Ordinal400th Factorization Roman numeralCD Binary110010000 Hexadecimal190 Mathematical Properties 400 is the square of 20 |
| ε´ | 5 | ν´ | 50 | φ´ | 500 |
| Ϝ´ or ς´ or στ´ | 6 | ξ´ | 60 | χ´ | 600 |
| ζ´ | 7 | ο´ | 70 | ψ´ | 700 |
| η´ | 8 | π´ | 80 | ω´ | 800 |
| θ´ | 9 | Ϟ´ | 90 | Ϡ´ | 900 |
The Greek sexagesimal place holder or zero symbol changed over time. The symbol used on papyri during the second century was a very small circle with an overbar several diameters long, terminated or not at both ends in various ways. Later, the overbar shortened to only one diameter, similar to our modern o macron (ō), which was still being used in late medieval Arabic manuscripts whenever alphabetic numerals were used. But the overbar was omitted in Byzantine manuscripts, leaving a bare ο. This gradual change from an invented symbol to ο does not support the hypothesis that the latter was the initial of ουδεν meaning "nothing". [Otto Neugebauer, The Exact Sciences in Antiquity (second edition, Providence, Rhode Island: Brown University Press, 1957) 13-14, plate 2.]