Roman Numerals

Roman numerals have their origin in Etruscan numerals. The early development of Roman numerals may have the originated with the shape of the hand, just as most early numerical systems have. The symbol-letter I may represent a single finger, V may represent the whole hand outstretched, and the symbol-letter X for both hands in the same manner. One hundred was given the letter C, because the word centum, meaning one hundred, starts with C. Now fifty is half of a hundred. If you take the symbol C for one hundred and cut it in half crosswise, it looks like an L, which is the letter for fifty. Much like C, the symbol for one thousand is the first letter of the word one thousand: mille - M.

Five hundred is half of a thousand. If you take the symbol M for one thousand and cut it in half through the middle, it looks like a D, which is the Roman numeral for five hundred.

Roman numeral basics

The Romans used the symbols below to represent their numerals.

**Roman Numeral Values**
ROMAN NUMERAL	ARABIC VALUE	LATIN WORD
I	1	UNUS
V	5	QUINQUE
X	10	DECEM
L	50	QUINQUAGINTA
C	100	CENTUM
D	500	QUINGENTI
M	1000	MILLE

Writing More Roman Numerals

To form the additional numbers between the seven basic numbers above, the following rules should be considered.

I, X, C and M may repeat up to 3 times.
- III = 3
- XXX= 30
- CCC= 300
- MMM = 3000
If one or more smaller numerals follow a numeral of greater value, add. Up to three numerals (I, X, C, M only) can be added in this manner.
- VIII = 8(V+III)
- XIII= 13 (X+III)
- CIII=103 (C+III)
If a smaller numeral (I, X, or C only) proceeds a numeral of greater value, subtract.
- IV= 4 (V-I)
- IX= 9 (X-I)
- XC= 90 (C-X)
- CD = 400 (D-C)

Nota Bene:

Never repeat V, L, or D.
- never:
  - VV for 10 (IX = 10)
You may only subtract one number at a time.
- never:
  - IIV for 3 (III = 3)
You may not subtract one number from another that is more than 10X greater.
- Allowed:
  - I from V, X (IV = 4; IX = 9)
  - X from L, C (XL = 40; XC = 90)
  - C from D, M (CD = 400; CM = 900)
- never:
  - IXX for 19 (XIX = 19)
  - IC for 99 (XCIX = 99)
  - XD for 490 (CDXC = 490)

Roman numerals use a system of position, where each position can have a symbol: thousands, hundreds, tens, ones. The digits combine:

MM (2000) CD (400) XX (20) IV (4) = MMCDXXIV = 2424

**Roman Numerals - 1-50**
1-10	11-20	21-30	31-40	41-50
I =1	XI =11	XXI= 21	XXXI= 31	XLI= 41
II=2	XII =12	XXII= 22	XXXII=32	XLII=42
III=3	XIII=13	XXIII= 23	XXXIII=33	XLIII=43
IV=4	XIV= 14	XXIV=24	XXXIV= 34	XLIV=44
V =5	XV =15	XXV= 25	XXXV=35	XLV=45
VI =6	XVI =16	XXVI=26	XXXVI= 36	XLVI=46
VII =7	XVII= 17	XXVII=27	XXXVII=37	XLVII=47
VIII =8	XVIII=18	XXVIII= 28	XXXVIII=38	XLVIII=48
IX =9	XIX= 19	XXIX= 29	XXXIX= 39	XLIX=49
X =10	XX= 20	XXX=30	XL= 40	L= 50

Nota Bene: A line placed on top of I, X, C or M increases the value by times 1000.

Roman Numeral Practice