Editing Hebrew numerals (section)

==Calculations==
The Hebrew numeric 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 {{Script/Hebrew|קעז}} which (from right to left) corresponds to 100 + 70 + 7 = 177.

Mathematically, this type of system requires 27 letters (1–9, 10–90, 100–900). In practice, the last letter, ''tav'' (which has the value 400), is used in combination with itself or other letters from ''qof'' (100) onwards to generate numbers from 500 and above. Alternatively, the 22-letter Hebrew numeral set is sometimes extended to 27 by using 5 ''sofit'' (final) forms of the Hebrew letters.<ref>According to Gandz (p. 96), cited above, this use of the sofit letters was not widely accepted and soon abandoned.</ref>

===Key exceptions===
By convention, the numbers 15 and 16 are represented as {{Script/Hebrew|ט״ו}}{{lrm}} (9 + 6) and {{Script/Hebrew|ט״ז}}{{lrm}} (9 + 7), respectively, in order to refrain from using the two-letter combinations {{Script/Hebrew|י-ה}}{{lrm}} (10 + 5) and {{Script/Hebrew|י-ו}}{{lrm}} (10 + 6), which are alternate written forms for the [[Tetragrammaton|Name of God]] in everyday writing. In the calendar, this manifests every [[full moon]] since all Hebrew months start on a [[new moon]] (see for example: [[Tu BiShvat]]).

This convention developed sometimes in the Middle Ages, before that it was common to write 15 and 16 as י"ה and י"ו.<ref>{{Cite journal |last=Nestle |first=E. |date=1884-01-01 |title=ו״ט = 15. |url=https://www.degruyter.com/document/doi/10.1515/zatw.1884.4.1.249/html |journal=Zeitschrift für die Alttestamentliche Wissenschaft |language=de |volume=4 |issue=Jahresband |pages=249–250 |doi=10.1515/zatw.1884.4.1.249 |issn=1613-0103}}</ref><ref>יעקב שמואל שפיגל. ''עמודים בתולדות הספר העברי - בשערי הדפוס''. פתח תקווה.  2014. עמ' [https://forum.otzar.org/download/file.php?id=71741 381-391]</ref>

Combinations which would spell out words with negative connotations are sometimes avoided by switching the order of the letters. For instance, 744 which should be written as {{Script/Hebrew|תשמ״ד}}{{lrm}} (meaning "you/it will be destroyed") might instead be written as {{Script/Hebrew|תשד״מ}} or {{Script/Hebrew|תמש״ד}} (meaning "end to demon").

===Use of final letters===
The Hebrew numeral system has sometimes been extended to include the five final letter forms—{{Script/Hebrew|ך}} for 500, {{Script/Hebrew|ם}} for 600, {{Script/Hebrew|ן}} for 700, {{Script/Hebrew|ף}} for 800, {{Script/Hebrew|ץ}} for 900. Usually though the final letter form are used with the same value as the regular letter form—{{Script/Hebrew|ך}} for 20, {{Script/Hebrew|ם}} for 40, {{Script/Hebrew|ן}} for 50, {{Script/Hebrew|ף}} for 80, {{Script/Hebrew|ץ}} for 90.

The ordinary additive forms for 500 to 900 are {{Script/Hebrew|ת״ק}}, {{Script/Hebrew|ת״ר}}, {{Script/Hebrew|ת״ש}}, {{Script/Hebrew|ת״ת}} and {{Script/Hebrew|תת״ק}}.