Number
900 in Roman numerals
900 is written CM
Type any other number or numeral below to convert it.
Above 3,999? Type the barred part in brackets, e.g. (IV)CC = 4,200.
How CM is built
Roman numerals are written one decimal place at a time, largest first.
- CMhundreds · 9C before M means 1,000 − 100 = 900. This saves writing DCCCC.
The pair CM uses subtraction: a smaller letter before a larger one is taken away from it. Only six pairs work this way: IV, IX, XL, XC, CD and CM. More on subtraction
Mistakes to avoid
- Not DCCCC (5 letters). That adds everything up without subtraction. The Romans sometimes wrote numbers this way, and clocks still show 4 as IIII, but today CM (2 letters) is the standard.
- There's no letter for zero. The zeros are simply left out, which is why 900 has 1 part, not 3.
About the number 900
- 900 is even and can be split into prime factors: 2 × 2 × 3 × 3 × 5 × 5, or in Roman numerals II × II × III × III × V × V.
- 900 is a square number: 30 × 30 (XXX × XXX).
- CM has 2 letters. 969 of the numbers up to 1,000 have longer numerals.
Counting from 891 to 900
| Number | Roman numeral |
|---|---|
| 891 | DCCCXCI |
| 892 | DCCCXCII |
| 893 | DCCCXCIII |
| 894 | DCCCXCIV |
| 895 | DCCCXCV |
| 896 | DCCCXCVI |
| 897 | DCCCXCVII |
| 898 | DCCCXCVIII |
| 899 | DCCCXCIX |
| 900 | CM |