I or .i = 1
V or v = 5
X or x = 10
L or l = 50
C or c = 100
D or d = 500
M or m = 1000
When a smaller valued or the same valued numeral follows another numeral, the numerals are to be added.
(2) VI = V + I = 5 + 1 = 6
(3) XXIII = 10 + 10 + 1 + 1 + 1 = 23