How Well Do You Know Your Roman Numerals?

The mathematician Boethius lived in the Roman Empire from 470 CE to 524 CE. Though the limitations of Roman numerals made it difficult for the Romans to practice abstract math, Boethius was hailed in his time as one of the great Roman mathematicians, due to his translations of mathematical works by the ancient Greeks, such as Euclid’s “Elements.”

The Lincoln Memorial features inscriptions of the names of the 36 states in the Union at the time of President Abraham Lincoln’s assassination in 1865. The date when each state joined the Union is engraved in Roman numerals below the state name.

Irrational numbers, which are numbers that can’t be expressed as the ratio of two integers, are not represented in the Roman numeral system. This means that the Romans could not work with certain numbers that were critical to the abstract mathematics practiced by the Greeks, such as pi. This limitation is one of the reasons the Roman civilization made few contributions to fields such as number theory and geometry.

In order to convert a word into Roman numerals, you need to use the same process you would in trying to read a Roman numeral. That means breaking the number down into its component parts. So for 3411, we have 3000 (MMM) + 400 (CD) + 11 (XI), represented together as MMMCDXI.

The concept of 0 was developed in ancient India and did not become commonly used in Western mathematics until Arabic numerals replaced Roman numerals in the 12th century. While the Romans were able to use their number systems for many practical purposes, such as engineering and record keeping, the system’s lack of 0 meant that the Romans made relatively few advancements in abstract mathematics.

While the Romans developed systems for writing very large numbers, the largest number that can be written with a single Roman numeral symbol is 1,000. The number is represented by the letter M.

If you're not accustomed to reading Roman numerals, a number this long can be pretty hard to break down, but the key is to start at the end and work back. So with MCMLXXXVI, we know that VI = 6, LXXX = 80, CM = 900, and M = 1000. If we add them all together, we get 1986.

Since the Roman numeral system made it difficult to express a very large number, it became standard to place a bar above a numeral to indicate it should be multiplied by 1000. For instance, since X means 10, to express the number 10,000 you would put a bar above the numeral, like so: X̅.

The Romans based their numeric system on the way fingers are often used to count, which also helps explain the emphasis on 5s (one hand) and 10s (two hands). The letter V was likely chosen to represent the number 5 because of the V shape made by the thumb and forefinger of an open hand, whereas X was chosen for 10 because it visually resembles two Vs touching.

Though they’re called Roman numerals, these symbols have been found dating as far back as the ninth century BCE, before the city of Rome was founded (in 753 BCE, according to legend). The numerals evolved from symbols used by Etruscan civilization that flourished in Italy and greatly influenced the Romans. The system was likely used to represent numbers to facilitate trade and commerce.

The way the Roman numeral system is devised, it is never necessary to use more than three of the same symbol in a row. So instead of writing IIII, the number four is expressed as IV, meaning one less than five. Similarly, the best way to represent 80 is LXXX, or three 10s more than 50, rather than eight Xs in a row.

The tradition of labeling the Super Bowl with Roman numerals was first introduced for Super Bowl V in 1971. Since then, all subsequent Super Bowls have used this Roman numeral labeling convention, and the first four Super Bowls were retroactively given Roman numeral labels.

Big Ben, a large clock in London, has four clock faces, each numbered with the Roman numerals for 1 through 12. However, one unusual feature of Big Ben is that the “4” is written as the conventional Roman numeral “IV,” while most other Roman numeral clocks and watches write “4” as “IIII” (even though this goes against the typical conventions of Roman numerals).

The Roman numeral system was powerful enough to outlast the empire that conceived it, holding on as the world's primary numeric system until the 14th century. However, the Arabic system had been introduced to Europe in the 11th century and slowly but surely became more commonplace. It had some key advantages that the Roman numeral system did not, such as the ability to represent 0 as a quantity and to depict very large numbers more concisely.

Centum is the Latin word for 100, but contrary to popular assumption, the C only came to represent 100 in the Roman numeral system coincidentally — the symbol for 100 is believed to have originally been a theta (θ). Many English words come from this Latin root, including century (100 years), cent (1/100 of a dollar), and centipede (so named because they were believed to have 100 feet on their body).

When the ancient Romans came up with this numeric system, they figured they could express any number using only seven symbols, represented by letters in the alphabet. L represents 50, C is 100, and M is 1000. The letter “R,” however, was not used in Roman numerals.

The Olympics have been labeled with Roman numerals since the first Games in Athens in 1896. The official name of the Athens Olympics was “The Games of the I Olympiad,” and all subsequent Olympic Games have used this naming convention. The most recent Olympics were the XXIV Winter Games, held in Beijing in 2022.

“Star Wars: Episode VI - Return of the Jedi” (1983) was the final movie in the original “Star Wars” trilogy. While there have since been multiple spinoff films and TV series set in the “Star Wars” universe, all of the movies that make up the “Skywalker Saga” have Roman numerals in their titles. The most recent was “Episode IX - The Rise of Skywalker” in 2019.

The seven alphanumeric symbols representing the Roman numerals are I, V, X, L, C, D, and M. In that order, they represent 1, 5, 10, 50, 100, 500, and 1000. This means that the D represents 500.