Roman numerals — worked examples
A good way to learn Roman numerals is to see them everywhere and practise on real examples. Here's a bank of typical Year-4 questions, with full working.
On a clock face
A clock face has the numbers 1 to 12 written as Roman numerals.
| Hour | Roman |
|---|---|
| 1 | I |
| 2 | II |
| 3 | III |
| 4 | IV (or IIII on some old clocks) |
| 5 | V |
| 6 | VI |
| 7 | VII |
| 8 | VIII |
| 9 | IX |
| 10 | X |
| 11 | XI |
| 12 | XII |
Notice that 4 is usually IV, but on some old clocks you'll see IIII instead. Both have been used historically. In modern maths we always write IV.
Chapter headings
A book has chapter headings: Chapter I, Chapter II, Chapter III, …, Chapter XX. How many chapters are there?
The last chapter is XX = 20. There are 20 chapters in total.
A chapter is labelled XVII. Which chapter number is that?
XVII = 10 + 5 + 1 + 1 = 17.
Monarchs
The names of kings and queens use Roman numerals to count them.
| Monarch | Roman | Number |
|---|---|---|
| Henry VIII | VIII | 8 |
| Louis XIV | XIV | 14 |
| Elizabeth II | II | 2 |
| Pope John Paul II | II | 2 |
| Pope Pius IX | IX | 9 |
| Catherine the Great (Catherine II) | II | 2 |
Queen Elizabeth II reigned in the 20th and 21st century. The previous queen with the same name (Elizabeth I) was in the 16th century. Why doesn't anyone write Elizabeth 2?
Because that's the convention — monarchs use Roman numerals after their name.
Centuries
A century is 100 years, and centuries are usually written in Roman numerals.
The 20th century is written as the XX century. Which years does it cover?
The 20th century covers years 1901–2000 (not 1900–1999 — the 1st century was years 1–100).
A monument is dated MCMXLV. What year is that?
Too big for our Year-4 set (M and D are involved). But for the sake of reading:
- M = 1000
- CM = 1000 − 100 = 900
- XL = 40
- V = 5
Total: 1000 + 900 + 40 + 5 = 1945 (the end of World War II).
Read-and-write pairs (1–100)
| Decimal | Roman | Decimal | Roman |
|---|---|---|---|
| 1 | I | 50 | L |
| 4 | IV | 54 | LIV |
| 9 | IX | 59 | LIX |
| 14 | XIV | 64 | LXIV |
| 19 | XIX | 69 | LXIX |
| 24 | XXIV | 74 | LXXIV |
| 29 | XXIX | 79 | LXXIX |
| 34 | XXXIV | 84 | LXXXIV |
| 39 | XXXIX | 89 | LXXXIX |
| 40 | XL | 90 | XC |
| 44 | XLIV | 94 | XCIV |
| 49 | XLIX | 99 | XCIX |
Notice the pattern of subtractive endings: every number ending in 4 has IV at the end, every number ending in 9 has IX at the end. Decades 40 and 90 use subtractive pairs XL and XC.
A mixed challenge
Write the year you are in now in Roman numerals using only the letters up to 100.
You probably can't — modern years (2024, 2025) are well over 1000 and need M. But you can write the last two digits. The year 2025 ends with 25 = XXV.