TABLE OF NUMBERS
CARDINAL NUMBERS1 ORDINAL NUMBERS4
NAME2 SYMBOL NAME5 SYMBOL6
Hindu-Arabic   Roman3
zero or naught or cipher 0  
     
one 1   I first 1st  
two 2   II second 2d or 2nd
three 3   III third 3d or 3rd
four 4   IV fourth 4th  
five 5   V fifth 5th  
six 6   VI sixth 6th  
seven 7   VII seventh 7th  
eight 8   VIII eighth 8th  
nine 9   IX ninth 9th  
ten 10   X tenth 10th  
eleven 11   XI eleventh 11th  
twelve 12   XII twelfth 12th  
thirteen 13   XIII thirteenth 13th  
fourteen 14   XIV fourteenth 14th  
fifteen 15   XV fifteenth 15th  
sixteen 16   XVI sixteenth 16th  
seventeen 17   XVII seventeenth 17th  
eighteen 18   XVIII eighteenth 18th  
nineteen 19   XIX nineteenth 19th  
twenty 20   XX twentieth 20th  
twenty-one 21   XXI twenty-first 21st  
twenty-two 22   XXII twenty-second 22d or 22nd
twenty-three 23   XXIII twenty-third 23d or 23rd
twenty-four 24   XXIV twenty-fourth 24th  
twenty-five 25   XXV twenty-fifth 25th  
twenty-six 26   XXVI twenty-sixth 26th  
twenty-seven 27   XXVII twenty-seventh 27th  
twenty-eight 28   XXVIII twenty-eighth 28th  
twenty-nine 29   XXIX twenty-ninth 29th  
thirty 30   XXX thirtieth 30th  
thirty-one 31   XXXI thirty-first 31st  
thirty-two etc 32   XXXII thirty-second 32d or 32nd
forty 40   XL fortieth 40th  
forty-one, etc. 41   XLI forty-first 41st  
forty-two etc 42   XLII forty-second 42d or 42nd
fifty 50   L fiftieth 50th  
sixty 60   LX sixtieth 60th  
seventy 70   LXX seventieth 70th  
eighty 80   LXXX eightieth 80th  
ninety 90   XC ninetieth 90th  
one hundred 100   C hundredth or one hundredth 100th  
one hundred and one or
one hundred one
101   CI hundred and first or
one hundred and first
101st  
one hundred and two etc 102   CII one hundred and second etc 102d or 102nd
two hundred 200   CC two hundredth 200th  
three hundred 300   CCC three hundredth 300th  
four hundred 400   CD four hundredth 400th  
five hundred 500   D five hundredth 500th  
six hundred 600   DC six hundredth 600th  
seven hundred 700   DCC seven hundredth 700th  
eight hundred 800   DCCC eight hundredth 800th  
nine hundred 900   CM nine hundredth 900th  
one thousand or ten hundred etc 1,000   M thousandth or one thousandth 1,000th  
two thousand etc 2,000   MM two thousandth etc 2,000th  
five thousand 5,000   five thousandth 5,000th  
ten thousand 10,000   ten thousandth 10,000th  
one hundred thousand 100,000   hundred thousandth or
one hundred thousandth
100,000th  
one million 1,000,000   millionth or one millionth 1,000,000th  
             

1The cardinal numbers are used in simple counting or in answer to "how many?" The words for these numbers may be used as nouns (he counted to twelve), as pronouns (twelve were found), or as adjectives (twelve boys).
2In formal contexts the numbers one to one hundred and in less formal contexts the numbers one to nine are commonly written out, while larger numbers are given in numerals. In nearly all contexts a number occurring at the beginning of a sentence is usually written out. Except in very formal contexts numerals are invariably used for dates. Hindu-Arabic numbers from 1,000 to 9,999 are often written without commas or spaces (1000, 9999). Year numbers are always written without commas (1783).
3The Roman numerals are written either in capitals or in lowercase letters.
4The ordinal numbers are used to show the order of succession in which such items as names, objects, and periods of time are considered (the twelfth month; the fourth row of seats; the 18th century).
5Each of the terms for the ordinal numbers excepting first and second is used in designating one of a number of parts into which a whole may be divided (a fourth; a sixth; a tenth) and as the denominator in fractions designating the number of such parts constituting a certain portion of a whole one fourth; three fifths). When used as nouns the fractions are usually written as two words, although they are regularly hyphenated as adjectives (a two-thirds majority). When fractions are written in numerals, the cardinal symbols are used (1/4, 3/5, 5/6).
6The Hindu-Arabic symbols for the cardinal numbers may be read as ordinals in certain contexts (January 1 = January first; 2 Samuel = Second Samuel). The Roman numerals are sometimes read as ordinals (Henry IV = Henry the Fourth); sometimes they are written with the ordinal suffixes (XIXth Dynasty).

DENOMINATIONS ABOVE ONE MILLION
American System1 British System1
NAME VALUE IN
POWERS
OF TEN
NUMBER
OF
ZEROS2
NUMBER OF
GROUPS OF
THREE 0'S
AFTER 1,000
NAME VALUE IN
POWERS
OF TEN
NUMBER
OF
ZEROS2
POWERS
OF
1,000,000
billion 109 9 2 milliard 109 9 --
trillion 1012 12 3 billion 1012 12 2
quadrillion 1015 15 4 trillion 1018 18 3
quintillion 1018 18 5 quadrillion 1024 24 4
sextillion 1021 21 6 quintillion 1030 30 5
septillion 1024 24 7 sextillion 1036 36 6
octillion 1027 27 8 septillion 1042 42 7
nonillion 1030 30 9 octillion 1048 48 8
decillion 1033 33 10 nonillion 1054 54 9
undecillion 1036 36 11 decillion 1060 60 10
duodecillion 1039 39 12 undecillion 1066 66 11
tredecillion 1042 42 13 duodecillion 1072 72 12
quattuordecillion 1045 45 14 tredecillion 1078 78 13
quindecillion 1048 48 15 quattuordecillion 1084 84 14
sexdecillion 1051 51 16 quindecillion 1090 90 15
septendecillion 1054 54 17 sexdecillion 1096 96 16
octodecillion 1057 57 18 septendecillion 10102 102 17
novemdecillion 1060 60 19 octodecillion 10108 108 18
vigintillion 1063 63 20 novemdecillion 10114 114 19
centillion 10303 303 100 vigintillion 10120 120 20
        centillion 10600 600 100

1The American system of numeration for denominations above one million was modeled on the French system but more recently the French system has been changed to correspond to the German and British systems. In the American system each of the denominations above 1,000 millions (the American billion) is 1,000 times the preceding one (one trillion = 1,000 billions; one quadrillion = 1,000 trillions). In the British system the first denomination above 1,000 millions (the British milliard) is 1,000 times the preceding one, but each of the denominations above 1,000 milliards (the British billion) is 1,000,000 times the preceding one (one trillion = 1,000,000 billions; one quadrillion = 1,000,000 trillions).
2For convenience in reading large numerals, the thousands, millions, etc., are usually separated by commas (21,530; 1,155,465) or especially in technical contexts by spaces (1 155 465). Serial numbers (as social security numbers are usually written with hyphens (042-24-4705).