Editing Roman numerals (section)

====Other subtractive forms====
There are numerous historical examples of {{rn|IIX}} being used for 8; for example, {{rn|XIIX}} was used by officers of the [[Legio XVIII|XVIII Roman Legion]] to write their number.<ref>{{Cite book |last1=Adkins |first1=Lesley |title=Handbook to life in ancient Rome |last2=Adkins |first2=Roy A |date=2004 |isbn=0-8160-5026-0 |edition=2 |page=270|publisher=Facts On File }}</ref><ref>{{Cite book |last=Boyne |first=William |title=A manual of Roman coins |date=1968 |page=13}}</ref> The notation appears prominently on the [[cenotaph]] of their senior [[centurion]] [[Marcus Caelius]] ({{circa|45 BC|lk=no}} – 9 AD). On the publicly displayed official Roman calendars known as [[Fasti]], {{rn|XIIX}} is used for the 18 days to the next [[Calends|Kalends]], and {{rn|XXIIX}} for the 28 days in February. The latter can be seen on the sole extant pre-Julian calendar, the [[Fasti Antiates Maiores]].<ref name="Degrassi">{{Cite book |title=Inscriptiones Italiae |date=1963 |publisher=Istituto Poligrafico dello Stato |editor-last=Degrassi |editor-first=Atilius |editor-link=Attilio Degrassi |volume=13: Fasti et Elogia |location=Rome |at=Fasciculus 2: Fasti anni Numani et Iuliani}}</ref>
There are historical examples of other subtractive forms: {{rn|IIIXX}} for 17,<ref name="lvnd1621">{{Cite book |last=Lundorphio |first=Michaele Gaspar |url=https://books.google.com/books?id=C41mAAAAcAAJ&pg=PA123 |title=Acta publica inter invictissimos gloriosissimosque&c. ... et Ferdinandum II. Romanorum Imperatores... |date=1621 |publisher=Ian-Friderici Weissii |page=123 |language=la}} <br />Page 123: "{{lang|la|Sub Dato Pragæ IIIXX Decemb. A. C. M. DC. IIXX}}". <br />Page 126, end of the same document: "{{lang|la|Dabantur Pragæ 17 Decemb. M. DC. IIXX}}".</ref> {{rn|IIXX}} for 18,<ref name="sulp1692">{{Cite book |last=Sulpicius à Munscrod |first=Raphael |url=https://archive.org/details/bub_gb_N43WFqB1wtoC/page/n69 |title=Vera Ac Germana Detecto Clandestinarvm Deliberationvm |date=1621 |page=16 |language=la}} <br />Page 16, line 1: "{{lang|la|repertum Originale Subdatum IIIXXX Aug. A. C. MDC.IIXX}}". <br />Page 41, upper right corner: "{{lang|la|Decemb. A. C. MDC.IIXX}}". Page 42, upper left corner: "{{lang|la|Febr. A. C. MDC.XIX}}". Page 70: "{{lang|la|IIXX. die Maij sequentia in consilio noua ex Bohemia allata....}}". <br />Page 71: "{{lang|la|XIX. Maij}}.</ref> {{rn|IIIC}} for 97,<ref name="tent1699">{{Cite book |last=Tentzel |first=Wilhelm Ernst |url=https://books.google.com/books?id=VN9lAAAAcAAJ&pg=PA39 |title=Als Ihre Königl. Majestät in Pohlen und ... |date=1699 |page=39 |language=de}} <br />Page 39: "{{lang|de|... und der Umschrifft: LITHUANIA ASSERTA M. DC. IIIC [1699].}}"</ref> {{rn|IIC}} for 98,<ref name="posn1698">{{Cite book |last=Posner |first=Johann Caspar |url=https://books.google.com/books?id=bmtOAAAAcAAJ&pg=PP9 |title=Mvndvs ante mvndvm sive De Chao Orbis Primordio |date=1698 |language=la}} <br />Title page: "{{lang|la|Ad diem jvlii A. O. R. M DC IIC}}".</ref><ref name="tent1700">{{Cite book |last=Tentzel |first=Wilhelm Ernst |url=https://books.google.com/books?id=qFVPAAAAcAAJ&pg=PA93 |title=Saxonia Nvmismatica: Das ist: Die Historie Des Durchlauchtigsten... |date=1700 |page=26 |language=de}} <br />Page 26: "{{lang|de|Die Revers hat eine feine Inscription}}: {{lang|la|SERENISSIMO DN.DN... SENATUS.QVERNF. A. M DC IIC D. 18 OCT [year 1698 day 18 oct].}}"</ref> and {{rn|IC}} for 99.<ref name="picc1699">{{Cite book |last=Piccolomini |first=Enea Silvio |url=https://books.google.com/books?id=0RNXAAAAcAAJ&pg=PA1 |title=Opera Geographica et Historica |date=1698 |publisher=J. M. Sustermann |edition=1st |location=Helmstadt |language=la |author-link=Pope Pius II}} Title page of first edition: "{{lang|la|Bibliopolæ ibid. M DC IC}}".</ref> A possible explanation is that the word for 18 in Latin is {{lang|la|duodeviginti}}{{px2}}{{mdash}}{{tsp}}literally "two from twenty"⁠{{mdash}}{{tsp}}while 98 is {{lang|la|duodecentum}} (two from hundred) and 99 is {{lang|la|undecentum}} (one from hundred).<ref name="kenn1879">{{Cite book |last=Kennedy |first=Benjamin H. |url=https://archive.org/details/publiclatin00kennrich |title=Latin grammar |date=1879 |publisher=Longmans, Green, and Co. |isbn=9781177808293 |location=London |page=[https://archive.org/details/publiclatin00kennrich/page/150 150]}}</ref> However, the explanation does not seem to apply to {{rn|IIIXX}} and {{rn|IIIC}}, since the Latin words for 17 and 97 were {{lang|la|septendecim}} (seven ten) and {{lang|la|nonaginta septem}} (ninety seven), respectively.

The {{code|ROMAN()}} function in [[Microsoft Excel]] supports multiple subtraction modes depending on the "{{tt|Form}}" setting. For example, the number "499" (usually {{rn|CDXCIX}}) can be rendered as {{rn|LDVLIV}}, {{rn|XDIX}}, {{rn|VDIV}} or {{rn|ID}}. The relevant Microsoft help page offers no explanation for this function other than to describe its output as "more concise".<ref>{{Cite web |title=ROMAN function |url=https://support.microsoft.com/en-us/office/roman-function-d6b0b99e-de46-4704-a518-b45a0f8b56f5 |website=Microsoft Support}}</ref>