How do you write 999 in a roman numeral?

Answer 1

CMXCIX

Which is made up from

M = 1000

C = 100

X = 10

I = 1

900 in roman numerals is CM - 100 before 1000

90 in roman numerals is XC - 10 before 100

9 in roman numerals is IX - 1 before 10