Hebrew numerals
The system of Hebrew numerals is a quasi-decimal alphabetic numeral system using the letters of the Hebrew alphabet.
In this system, there was no notation for zero, and the numeric values for individual letters are added together. Each unit (1, 2, ..., 9) is assigned a separate letter, each tens (10, 20, ..., 90) a separate letter, and each hundreds (100, 200, ..., 900) a separate letter. Gematria (Jewish numerology) uses these transformations extensively.
| Hebrew | Decimal | Glyph |
|---|---|---|
| Aleph | 1 | א |
| Bet | 2 | ב |
| Gimmel | 3 | ג |
| Dalet | 4 | ד |
| Hey | 5 | ה |
| Vav | 6 | ו |
| Zayin | 7 | ז |
| Het | 8 | ח |
| Tet | 9 | ט |
| Yod | 10 | י |
| Kaf | 20 | כ |
| Lamed | 30 | ל |
| Mem | 40 | מ |
| Nun | 50 | נ |
| Samekh | 60 | ס |
| Ayin | 70 | ע |
| Phei | 80 | פ |
| Tsadei | 90 | צ |
| Kuf | 100 | ק |
| Resh | 200 | ר |
| Shin | 300 | ש |
| Tav | 400 | ת |
| Kaf Sofeet | 500 | ך |
| Mem Sofeet | 600 | ם |
| NuN Sofeet | 700 | ן |
| Phei Sofeet | 800 | ף |
| Tsadei Sofeet | 900 | ץ |
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, 177 is represented as קעז which corresponds to 100 + 70 + 7 = 177.
The numbers 15 and 16 are represented as טו (9+6) and טז (9+7) respectively, instead of יה and יו. This is done in order to refrain from using the "sacred" combinations that are a part of the name of God in Judaism.
This system requires 27 letters, so the 22-letter Hebrew alphabet is sometimes extended to 27 by using 5 sofeet (final) forms of the Hebrew letters. Alternatively (and more often), the last letter, tav (which has the value 400) is used in combination with itself and/or other letters from qof (100) onwards, to generate numbers from 500 and above.
A gershayim mark (similar to a double quote mark) is often inserted before the last (leftmost) letter to indicate that the sequence of letters represents a number rather than a word. When only one letter is used (as for the numbers 1-9, 10, 20, etc.), a geresh mark (similar to a single quote mark) follows the letter.
Thousands are counted separately, and the thousand count precedes the rest of the number. When specifying years of the Hebrew calendar, the thousands are often simply omitted if the year is in the present millennium.
This system is nowadays used mainly for specifying the days and years of the Hebrew calendar, and in numerology (gematria).