Roman numerals: read, write and convert, worked example
22 October 2026
Roman numerals can look confusing at first, but they follow simple rules. Here is a clear example to help your child see how to read, write and convert Roman numerals step by step.
Worked example
What number is written as XLII in Roman numerals?
Step 1: Write the value of each symbol. X = 10, L = 50, I = 1, I = 1
Step 2: Look for any subtracting pairs.
X before L means 10 less than 50, so XL = 40.
Step 3: Add the rest. XL = 40, I = 1, I = 1
Step 4: Add all the values together. 40 + 1 + 1 = 42
The correct answer is 42.
| Symbol | Value |
|---|---|
| X | 10 |
| L | 50 |
| I | 1 |
| I | 1 |
| XL | 40 |
| XL + I + I | 42 |
Key insight: Once your child understands how each Roman numeral symbol works, they can spot patterns and break down any similar question. They will now be able to recognise and solve other Roman numerals questions with confidence.
