The numbers that we use today are not the same as the ones the Romans used. Roman Numerals were used all over the Roman Empire.
In England, they are still used occasionally, for example, on film credits and clock faces.
Remember that the Romans didn't have a symbol for the number 0.
The Romans used these symbols:
I | = 1 |
V | = 5 |
X | = 10 |
L | = 50 |
C | = 100 |
D | = 500 |
M | = 1000 |
All other numbers can be built using these symbols by adding or subtracting.
You should know the following:
1 | I | |
2 | II | |
3 | III | |
4 | IV | I before V is 1 less than 5 |
5 | V | |
6 | VI | I after V is 1 more than 5 |
7 | VII | II after V is 2 more than 5 |
8 | VIII | III after V is 3 more than 5 |
9 | IX | I before X is 1 less than 10 |
10 | X | |
11 | XI | I after X is 1 more than 10 |
12 | XII | II after X is 2 more than 10 |
We build bigger numbers by adding 10s or Xs in Roman Numerals.
20 | XX = X + X = 20 |
21 | XXI = XX + I = 20 + 1 |
30 | XXX = X + X + X = 30 |
37 | XXXVII = XXX + VII = 30 + 7 |
40 | XL = X before L is 10 less than 50 or 50 - 10 = 40 |
48 | XLVIII = XL + VIII = 40 + 8 = 48 |
49 | XLIX = XL + IX = 40 + 9 = 49 |
50 | L |
54 | LIV = L + IV = 50 + 4 = 54 |
60 | LX = X after L is 10 more than 50 or 50 + 10 = 60 |
67 | LXVII = LX + VII = 60 + 7 = 67 |
70 | LXX = L + XX = 50 + 20 = 70 |
80 | LXXX = L + XXX = 50 + 30 = 80 |
84 | LXXIV = L + XXXIV = 50 + 34 = 84 |
90 | XC = X before C is 10 less than 100 or 100 - 10 = 90 |
96 | XCVI = XC + VI = 90 + 6 = 96 |
We build even bigger numbers by adding 100s, 500s or 1000s or Cs, Ds and Ms in Roman Numerals.
200 | CC = C + C = 100 |
311 | CCCXI = C + C + C + X + I = 300 + 10 + 1 |
400 | CD = C before D is 100 less than 500 or 500 - 100 = 400 |
444 | CDXLIV = CD + XL + IV = 400 + 40 + 4 = 444 |
500 | D = 500 |
800 | DCCC = D + C + C + C = 500 + 300 = 800 |
900 | CM = C before M is 100 less than 1000 or 1000 - 100 = 900 |
1000 | M = 1000 |
Larger numbers are built from smaller numbers.
1200 | MCC = M + C + C = 1000 + 200 = 1200 |
1311 | MCCCI = M + C + C + C + X + I = 1000 + 300 + 1 |
1400 | MCD = M + CD = 1000 + 400 = 1400 |
1900 | MCM = M + CM = 1000 + 900 = 1900 |
Example
Convert 1895 and 1948 to Roman Numerals.
Answer
Build the numbers using smaller numbers that you know.
Then string them together in a line.
1895 = 1000 + 800 + 90 + 5 = M + DCCC + XC + V = MDCCCXCV
1948 = 1000 + 900 + 40 + 8 = M + CM + XL + VIII = MCMXLVIII