What does CCCXXXIX mean in roman numerals?

Answer 1

Add together the individual numerals (M = 1000, D = 500, C = 100, L = 50, X = 10, V = 5, I = 1) unless a smaller numeral precedes a larger one in which case subtract it from the larger one.

→ CCCXXXIX = 100 + 100 + 100 + 10 + 10 + 10 + (-1 + 10) = 339

Answer 2

C represents 100, I is 1 and X is 10. This would be shown as 339.