Il numero romano CCCLXXX nel sistema decimale vale: 380.
CCCLXXX in latino si scrive trecenti octoginta,
mentre in italiano trecentottanta.
CCCLXI, CCCLXII, CCCLXIII, CCCLXIV, CCCLXV, CCCLXVI, CCCLXVII, CCCLXVIII, CCCLXIX, CCCLXX, CCCLXXI, CCCLXXII, CCCLXXIII, CCCLXXIV, CCCLXXV, CCCLXXVI, CCCLXXVII, CCCLXXVIII, CCCLXXIX, CCCLXXXI, CCCLXXXII, CCCLXXXIII, CCCLXXXIV, CCCLXXXV, CCCLXXXVI, CCCLXXXVII, CCCLXXXVIII, CCCLXXXIX, CCCXC, CCCXCI, CCCXCII, CCCXCIII, CCCXCIV, CCCXCV, CCCXCVI, CCCXCVII, CCCXCVIII, CCCXCIX