How it is calculated
Only the standard form is accepted. IIII in place of IV, and other old spellings, fail the check that translates them back.
I=1, V=5, X=10, L=50, C=100, D=500, M=1000
Where the numbers come from
- Direction
- Ordinary number
- Roman numeral
Example
1994 is written as MCMXCIV.
Questions
Zero and numbers above 3999?
In classical notation, without bars over the letters, they are not there.
Does letter case matter?
No. Lowercase is fine too.
Why MCMXCIV, and not MDCCCCLXXXXIIII?
The modern form is shorter, and it subtracts when a smaller symbol stands on the left.