Roman numerals — Classical languages, 7–10 years
See how Romans wrote numbers with a small set of repeated and combined signs. Classical languages, 7–10 years.
Numbers made from signs
Roman numerals build numbers from signs such as I for one, V for five, X for ten, L for fifty and C for one hundred. Usually, signs are added from left to right: VIII is 5 + 1 + 1 + 1, or 8.
Why write numbers this way?
Romans needed numbers on buildings, lists, coins and records, but they did not have our place-value notation. A few familiar marks were easy to carve and recognise. The system was useful for labels and dates, even though calculations with it were awkward.
Read XXIV
Take XXIV one sign at a time. X is 10, and the next X is another 10, so we have 20. V adds 5, making 25. The final I is 1, so XXIV is 26. Nothing needs to be guessed: add each sign because each one is followed by an equal or smaller sign.
Always add?
A learner may add every mark because that works for VIII and XXIV. It is a sensible first rule, but some pairs use subtraction: IV means 5 − 1, so it is 4, and IX means 10 − 1, so it is 9. The order can change the job of a sign.
Still around us
Roman numerals still label clock faces, book chapters, kings, films and the year of a building or event. A clock may show IV as 4, while a book may use Chapter IX for chapter 9. They work well as labels because they stand out from ordinary numbers.
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