Card 2 of 8
Roman numerals
The seven letters, how they combine, and the years that catch children out.
| Number | Roman |
|---|---|
| 1 | I |
| 4 | IV |
| 5 | V |
| 9 | IX |
| 10 | X |
| 14 | XIV |
| 19 | XIX |
| 40 | XL |
| 50 | L |
| 90 | XC |
| 100 | C |
| 400 | CD |
| 500 | D |
| 900 | CM |
| 1000 | M |
| 2026 | MMXXVI |
The seven letters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Memory hook: I Value Xylophones Like Cows Do Milk.
The subtraction rule. A smaller letter before a larger one means subtract:
- IV = 4 (not IIII), IX = 9, XL = 40, XC = 90, CD = 400, CM = 900
Reading a long one — work left to right in chunks:
MMXXVI → MM (2000) + XX (20) + V (5) + I (1) = 2026
Rules examiners test:
- Never four of the same letter in a row (so 40 is XL, never XXXX)
- Only I, X, C are ever used for subtraction (never V, L, D)
- I only subtracts from V and X; X only from L and C; C only from D and M