The Romans used characters:
''I'' = one ''V'' = five ''X'' = ten ''L'' = fifty ''C'' = one hundred ''D'' = five hundred ''M'' = one thousand
These characters were used in an additive form, except for 4, 9 ,40, 90,.... In these cases we subtract the smaller number (on the left) from the bigger number (on the right).
Example:
14 = XIV 2009 = MMIX 1459 = MCDLIX