42 in Roman numerals
XLII
The number 42 is written XLII in Roman numerals.
How XLII breaks down
| Symbols | Value |
|---|---|
XL | 40 |
II | 2 × 1 = 2 |
XLII | 42 |
This numeral uses the subtractive rule: a smaller symbol placed before a larger one is subtracted from it. Only six such pairs are legal — IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).
Nearby numbers
| Number | Roman numeral |
|---|---|
| 37 | XXXVII |
| 38 | XXXVIII |
| 39 | XXXIX |
| 40 | XL |
| 41 | XLI |
| 42 | XLII |
| 43 | XLIII |
| 44 | XLIV |
| 45 | XLV |
| 46 | XLVI |
| 47 | XLVII |
The seven symbols
I | 1 | C | 100 |
V | 5 | D | 500 |
X | 10 | M | 1,000 |
L | 50 |
42 in other notations
| Roman | XLII |
| Binary | 101010 |
| Hexadecimal | 2A |
| Octal | 52 |
| Written out | forty-two |
Writing it by hand
Work down through the symbol values, taking as many of each as will fit before moving to the next. For 42:
XL = 40 remaining: 2
2 × I = 2 remaining: 0The result reads XLII — 4 characters, against 2 digits in Arabic numerals.
Frequently asked questions
What is 42 in Roman numerals?
XLII
How do you read XLII?
Work left to right, adding each symbol — except where a smaller symbol precedes a larger one, in which case it is subtracted. XL is 40, II is 2, giving 42 in total.
How do you write 42 in words?
forty-two.
Why is there no zero?
Roman numerals have no symbol for zero. The concept reached Europe only with Hindu-Arabic numerals, centuries after the system was in use — which is a large part of why it was eventually replaced for arithmetic.