Roman numerals, writing roman numerals, etc… Please follow the list for detailed expressions, lists and examples;
A numeral system is a writting system for expressing numbers.
We generally use 10 digits ( 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ) for writting a number in many parts of the world which are called arabic numbers or arabic numerals.
However sometimes we can use or see another numeral system for writting numbers which are used by the ancient Romans to write numbers ( like I=1, III=3, V=5, X=10, C=100) which are called roman numbers or roman numerals.
The Letters Used in Roman Numerals ( from lower to higher ) 







NOTE 1:
Roman numerals are essentially known as uppercase letters: I, V, X, L, C, D and M.
However, it is possible to use lowercase letters: i, v, x, l, c, d and m.
NOTE 2:
We can make or see a combination is made of smaller groups of these letters ( such as XX – xx, LXVI – lxvi, CCCVII – cccvii), each group in increasing order from right to left. The whole combination represents a number.
Examples:
 XX = X (10) + X (10) = 20
 LXX= L (50) + XX (20) = 70
 CXCII = C (100) + XC (90) + II (2) = 192
 MDLXXXIV = M (1000) + D (500) + LXXX (80) + IV (4) = 1584
NOTE 3:
The letters can be repeated three times to increase the value but the letter can not be repeated more than three times.
It means;
 XXX ( CORRECT )
 XXXX ( INCORRECT)
 CCC ( CORRECT )
 CCCC ( INCORRECT)
You can see some important or most used numbers or numerals below;
ROMAN NUMERAL  ROMAN NUMERAL  ARABIC NUMERAL 
Uppercase  Lowercase  ———————— 
I  i  1 
II  ii  2 
III  iii  3 
IV  iv  4 
V  v  5 
VI  vi  6 
VII  vii  7 
VIII  viii  8 
IX  ix  9 
X  x  10 
XI  xi  11 
XII  xii  12 
XIII  xiii  13 
XIV  xiv  14 
XV  xv  15 
XVI  xvi  16 
XVII  xvii  17 
XVIII  xviii  18 
XIV  xiv  19 
XX  xx  20 
XXX  xxx  30 
XL  xl  40 
L  l  50 
LX  lx  60 
LXX  lxx  70 
LXXX  lxxx  80 
XC  xc  90 
C  c  100 
CC  cc  200 
CCC  ccc  300 
CD  cd  400 
D  d  500 
DC  dc  600 
DCC  dcc  700 
DCCC  dccc  800 
CM  cm  900 
M  m  1000 
You can see also detailed roman numberals list below;
From 1 10
From 11 to 20
From 21 to 30
From 31 to 40
From 41 to 50
From 51 to 60
From 61 to 70
From 71 to 80
From 81 to 90
From 91 to 100
From 10 to 100
From 100 to 1000
From 1000 to 5000
From 10,000 to 1,000,000
From 5,000,000 to 1,000,000,0000
Examples with Writing Roman Numerals
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