While I’ve been building a Street Treasure Hunt for the London-based upper school of EIFA International School it occurred to me that we don’t have any blog posts on Roman Numerals… Decoding detective work is certainly something for which treasure hunters on the London Street Hunt will be tested!
EIFA kids, who hail from 40 nationalities and speak a collection of 30 languages, have their lessons divided with half their day in English, half their day in French. When they reach the upper school their IB curriculum adds Spanish to their languages and are additionally asked to choose between Latin and German as their 4th language. So, though international to the core, not all EIFA kids will have covered how Roman Numerals work.
EIFA Kids, Do I have your attention if I say that this post may just plant an answer to one of our THATMuse bonus questions?!! In other words, read this post, and get a leg up on your competition!
The History of Roman Numerals
Between the 8th & 9th Centuries BC, when the Roman Empire was being established on the Palatine Hill, the Roman Numeral system evolved. As you can guess, the counting system was crucial to standardising methods of counting for trade and communication – not forgetting counting time with sundials (predecessors of clocks)?!
Impressively, Roman Numerals outlasted their Roman Empire beginnings, being used by everyone until the 14th Century… and many since then. Just think of the face of clock in any European train station.
How Roman Numerals Work
So, for those EIFA students who chose to take German over Latin, here’s the nitty gritty of how Roman Numerals work:
Post-Lockdown we’re all accustomed to video tutorials, so here’s the low-down on how Roman Numerals work in French and another brief on Roman Numerals in English.
Alternatively, Britannica Kids gives the following summary:
The Roman numeral system uses seven letters as numerals: I = 1; V = 5; X = 10; L = 50; C = 100; D = 500; M = 1,000. The numerals can be written as either capital or lowercase letters. A bar over a numeral multiplies its value by 1,000: for example, V = 5,000 and X = 10,000.
When a numeral is followed by one of equal or lesser value, their values are added together: II = 2; VI = 6; CLV = 155. This system could create very long numbers if numerals could be repeated without limit (for example, IIII or CCCC). To avoid this problem, the system uses subtraction within the numbers. A numeral is never used more than three times in a row. Instead of repeating the numeral a fourth time, the value is expressed by a smaller numeral followed by a larger numeral. The smaller numeral is subtracted from the larger one. For example, instead of IIII, the number 4 is written as IV (5 − 1). The number 400 is written as CD (500 − 100).
A theory of where they come from
As for how Romans developed their numerical system, it’s not exactly clear. Some academics think the marks correlated to hand gestures with I, II and III looking like single fingers and the V representing a thumb stretched away from the rest of one’s fingers. Six to Nine used that V plus the single fingers on the other hand; the X being interpreted by intersecting thumbs.
On the London Street Hunt, which we’ll be pulling from in THATMuse blog posts over the next month, you’ll certainly be asked to decode some Roman Numerals across Bloomsbury, but you may also be tested on some of the above trivia! Did I catch your ears with that??? London Street Treasure Hunt posts will return to the importance of the Parthenon to architecture and introduce Henry VIII (what, what number is that in Arabic numbers? Answer in comments and you’ll get an honorable mention during the hunt!)