Rules
Add when a smaller numeral comes after a larger one
If a smaller number comes after a bigger one, you add it.
Example:
VI = 5 + 1 = 6
XV = 10 + 5 = 15
Subtract when a smaller numeral comes before a larger one
If a smaller number comes before a bigger one, you subtract it.
Example:
IV = 5 − 1 = 4
IX = 10 − 1 = 9
You can only subtract I from V or X, X from L or C, and C from D or M.
To pass this step, you must understand the following:
1. Recognise and use key Roman numerals up to 1,000
They should know these values by heart:
| Roman | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |
2. Understand and apply the main rules (see previous answer):
Add when a smaller numeral follows a bigger one: e.g. VI = 6
Subtract when a smaller numeral is before a bigger one: e.g. IV = 4
No symbol repeated more than 3 times in a row
V, L, and D are never repeated
3. Be able to read and write numbers in Roman numerals
Up to M (1,000)
Including common values like XIV (14), XL (40), XC (90), CD (400), CM (900)
Write dates like MMXXV = 2025
4. Use Roman numerals in real-life examples
They should be able to:
Understand clock faces with Roman numerals
Read Roman numerals in book chapters, movie titles, monarch names (e.g. King Henry VIII)
Read years in Roman numerals (e.g. MCMXCIX = 1999)
