Professor Baker’s quick guide to Roman numerals:

I = 1

V = 5

X = 10

L = 50

C = 100

A few rules:

1) Consecutive numbers indicate addition (not multiplication), so

II = 2 and XV = 15 (not 50)

2) Numbers are not repeated more than three times, so

3 = III, but 4 would not be IIII.

3) When numbers are presented in order of EQUAL or DECREASING numerical value, start at the front and add:

III =

1 + 1 + 1, or 3

(because the numbers are all the same)

OR

V I =

5 + 1, or 6

(because the first number, 5, is greater than the second number, 1)

4) When numbers are presented in order of INCREASING numerical value, start at the back and subtract:

I V =

5 – 1, or 4

(because the first number, 1, is less than the second number, 5)

Return to Baker’s ENG 208