Il numero romano MDCCLXXX nel sistema decimale vale: 1780.
MDCCLXXX in latino si scrive mille septingenti octoginta,
mentre in italiano millesettecentottanta.
MDCCLXI, MDCCLXII, MDCCLXIII, MDCCLXIV, MDCCLXV, MDCCLXVI, MDCCLXVII, MDCCLXVIII, MDCCLXIX, MDCCLXX, MDCCLXXI, MDCCLXXII, MDCCLXXIII, MDCCLXXIV, MDCCLXXV, MDCCLXXVI, MDCCLXXVII, MDCCLXXVIII, MDCCLXXIX, MDCCLXXXI, MDCCLXXXII, MDCCLXXXIII, MDCCLXXXIV, MDCCLXXXV, MDCCLXXXVI, MDCCLXXXVII, MDCCLXXXVIII, MDCCLXXXIX, MDCCXC, MDCCXCI, MDCCXCII, MDCCXCIII, MDCCXCIV, MDCCXCV, MDCCXCVI, MDCCXCVII, MDCCXCVIII, MDCCXCIX