What does CXLIII mean?

CXLIII is the Roman numeral for 143 — 100 + 40 + 1 + 1 + 1.

How do you write 143 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: C (100), then XL (40), then I (1), then I (1), then I (1). That gives CXLIII.

143 in Roman numerals

CXLIII

Number (1–3,999 for numerals)

Roman numeral

143 is written CXLIII in Roman numerals. That is 5 symbol groups added together, reading left to right from the largest value down.

How it breaks down

CXLIII = 100 + 40 + 1 + 1 + 1 = 143
Group	Value	Subtraction	Running total
C	100	—	100
XL	40	L − X	140
I	1	—	141
I	1	—	142
I	1	—	143

Why the smaller symbol comes first

CXLIII uses subtractive notation in one place: XL means L minus X, or 40. 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 — 3×
V	5	no
X	10	yes — 1×
L	50	yes — 1×
C	100	yes — 1×
D	500	no
M	1,000	no

The same number, other ways

In words: One hundred forty-three
Roman numeral: CXLIII
Symbol count: 6 characters
Binary: 10001111
Hexadecimal: 8F

The numbers either side

Number	Roman numeral
141	CXLI
142	CXLII
143	CXLIII ←
144	CXLIV
145	CXLV

Common questions

What is 143 in Roman numerals?: 143 is CXLIII.
What does CXLIII mean?: CXLIII is the Roman numeral for 143 — 100 + 40 + 1 + 1 + 1.
How do you write 143 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: C (100), then XL (40), then I (1), then I (1), then I (1). That gives CXLIII.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked