Il numero romano MCCLXXX nel sistema decimale vale: 1280.
MCCLXXX in latino si scrive mille ducenti octoginta,
mentre in italiano milleduecentottanta.
MCCLXI, MCCLXII, MCCLXIII, MCCLXIV, MCCLXV, MCCLXVI, MCCLXVII, MCCLXVIII, MCCLXIX, MCCLXX, MCCLXXI, MCCLXXII, MCCLXXIII, MCCLXXIV, MCCLXXV, MCCLXXVI, MCCLXXVII, MCCLXXVIII, MCCLXXIX, MCCLXXXI, MCCLXXXII, MCCLXXXIII, MCCLXXXIV, MCCLXXXV, MCCLXXXVI, MCCLXXXVII, MCCLXXXVIII, MCCLXXXIX, MCCXC, MCCXCI, MCCXCII, MCCXCIII, MCCXCIV, MCCXCV, MCCXCVI, MCCXCVII, MCCXCVIII, MCCXCIX