Number
109 in Roman numerals
109 is written CIX
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 CIX is built
Roman numerals are written one decimal place at a time, largest first.
- Chundreds · 1C is 100.
- IXones · 9I before X means 10 − 1 = 9. This saves writing VIIII.
100 + 9 = 109
The pair IX 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 CVIIII (6 letters). That adds everything up without subtraction. The Romans sometimes wrote numbers this way, and clocks still show 4 as IIII, but today CIX (3 letters) is the standard.
- There's no letter for zero. The zero is simply left out, which is why 109 has 2 parts, not 3.
About the number 109
- 109 is a prime number: only 1 and 109 divide it exactly.
- CIX has 3 letters. 907 of the numbers up to 1,000 have longer numerals.
Counting from 101 to 110
| Number | Roman numeral |
|---|---|
| 101 | CI |
| 102 | CII |
| 103 | CIII |
| 104 | CIV |
| 105 | CV |
| 106 | CVI |
| 107 | CVII |
| 108 | CVIII |
| 109 | CIX |
| 110 | CX |