How to Write Roman Numerals
Learn the simple rules step by step!
The 7 Roman Letters
Roman numerals use only 7 letters. Each letter has a number value:
Rule 1: Adding Numbers
When a small letter comes AFTER a big letter, you ADD them together.
Let's Break Down VI Step by Step!
Because I comes AFTER V, we add: 5 + 1 = 6
Rule 2: Taking Away Numbers
When a small letter comes BEFORE a big letter, you SUBTRACT (take away) the small number.
Let's Break Down IV Step by Step!
Because I comes BEFORE V, we subtract: 5 - 1 = 4
Only I, X, and C can be used to subtract. They can only subtract from certain letters.
Rule 3: Repeating Letters
You can write the same letter up to 3 times in a row to add more value.
V, L, and D are NEVER repeated. Instead we use X, C, and M.
All Rules Working Together!
This example shows ALL THREE rules working together. Let's Break Down XLIII Step by Step!
Rule 2: Subtraction
X comes BEFORE L, so we subtract
Rule 3: Repetition
Same letter repeated 3 times
Rule 1: Addition
Combine the parts together
Step-by-Step Breakdown
Step-by-Step Breakdown:
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Step-by-Step Breakdown:
Common Mistakes to Avoid
Learn from these common errors!
Memory Tips
Start with the largest values and work your way down
Remember that only I, X, and C can be used for subtraction
Never repeat V, L, or D
When in doubt, use addition rather than subtraction
Practice with years and dates to build familiarity
Practice Exercises
Test your understanding with these examples:
Ready to Practice More?
Now that you know the rules, it's time to practice! Try our interactive tools to become a Roman numeral expert.