Today we use the decimal number system where every number is created using the digits from 0 to 9
However, in Roman times Roman numerals were used.
The Romans used these seven different symbols to represent numbers:
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000
We need to know how to read and write the numbers up to 100:
| 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 can build bigger numbers by the other symbols – L C D M
| 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 |
Today, Roman numerals are still used occasionally, for example on clock faces.
Have a look around to see if you can spot more ( watch the credits at the very end of a film! )
The Romans didn’t have a symbol for 0.
Let’s have a go at writing some Roman numerals.
Use the table above to help.
Write 27 in Roman numerals:
XXVII ( X = 10 V = 5 I = 1 )
X + X + V + I + I
Challenge yourself:
Write 134 in Roman numerals.
CXXXIV ( C = 100 X = 10 IV = 4)
C + X + X + X + IV
