What does CCCXXIX mean?

CCCXXIX is the Roman numeral for 329 — 100 + 100 + 100 + 10 + 10 + 9.

How do you write 329 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: C (100), then C (100), then C (100), then X (10), then X (10), then IX (9). That gives CCCXXIX.

329 in Roman numerals

CCCXXIX

Number (1–3,999 for numerals)

Roman numeral

329 is written CCCXXIX in Roman numerals. That is 6 symbol groups added together, reading left to right from the largest value down.

How it breaks down

CCCXXIX = 100 + 100 + 100 + 10 + 10 + 9 = 329
Group	Value	Subtraction	Running total
C	100	—	100
C	100	—	200
C	100	—	300
X	10	—	310
X	10	—	320
IX	9	X − I	329

Why the smaller symbol comes first

CCCXXIX uses subtractive notation in one place: IX means X minus I, or 9. A smaller symbol placed before a larger one is subtracted from it rather than added, which is why IX is nine and not eleven.

Only six such pairs are valid — IV, IX, XL, XC, CD and CM. That restriction is what makes the notation unambiguous: IIII and IC both look like they should work, but neither is standard, and only one spelling of any number is correct.

The symbols

Symbol	Value	Used here
I	1	yes — 1×
V	5	no
X	10	yes — 3×
L	50	no
C	100	yes — 3×
D	500	no
M	1,000	no

The same number, other ways

In words: Three hundred twenty-nine
Roman numeral: CCCXXIX
Symbol count: 7 characters
Binary: 101001001
Hexadecimal: 149

The numbers either side

Number	Roman numeral
327	CCCXXVII
328	CCCXXVIII
329	CCCXXIX ←
330	CCCXXX
331	CCCXXXI

Common questions

What is 329 in Roman numerals?: 329 is CCCXXIX.
What does CCCXXIX mean?: CCCXXIX is the Roman numeral for 329 — 100 + 100 + 100 + 10 + 10 + 9.
How do you write 329 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: C (100), then C (100), then C (100), then X (10), then X (10), then IX (9). That gives CCCXXIX.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked