90 in Roman numerals
90 is written XC. The smaller X comes before the bigger C, so take it away: XC is 90, ten before a hundred.
The answer
XC
90 in Roman numerals is XC.
How XC is built
To write it, 90 is 9 tens and no ones, so it is just the tens: XC. There is no zero to write.
To read it, XC is one take-away pair, so there is nothing else to add.
| Chunk | Worth | Why |
|---|---|---|
| XC | 90 | X before C: take away |
The mistake to watch for
Writing 90 as LXXXX
Wrong: LXXXX
LXXXX writes X four times in a row. Never more than three: 90 is XC, ten before a hundred.
Check it with the converter
Type LXXXX to see why LXXXX is not 90. The rule numbers it gives are the three rules on the Roman numerals page.
Converter set to XC (90).
Keep going
Questions parents ask
What is 90 in Roman numerals?
90 is XC.
What comes before and after XC?
89 is LXXXIX and 91 is XCI. The whole numeral changes: LXXXIX becomes XC.
Does XC use subtraction?
Yes. X comes before the bigger C, so XC is 90.
What is the biggest letter in XC?
C, which is 100. XC has 2 letters.
Careful reading is an 11+ skill
Reading both letters of XC in order is the careful checking 11+ papers reward. The free diagnostic covers all four subjects, with no card needed.