349 in Roman numerals

How CCCXLIX is built

Roman numerals are written one decimal place at a time, largest first.

1. CCChundreds · 3C written 3 times: 3 × 100 = 300.
2. XLtens · 4X before L means 50 − 10 = 40. This saves writing XXXX.
3. IXones · 9I before X means 10 − 1 = 9. This saves writing VIIII.

300 + 40 + 9 = 349

The pairs XL and IX use 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 CCCIL. It looks like a shortcut, but I may only come before V or X, not L. The correct form is CCCXLIX.
• Not CCCXXXXVIIII (12 letters). That adds everything up without subtraction. The Romans sometimes wrote numbers this way, and clocks still show 4 as IIII, but today CCCXLIX (7 letters) is the standard.