Il numero romano CLXXX nel sistema decimale vale: 180.
CLXXX in latino si scrive centum octoginta,
mentre in italiano centottanta.
CLXI, CLXII, CLXIII, CLXIV, CLXV, CLXVI, CLXVII, CLXVIII, CLXIX, CLXX, CLXXI, CLXXII, CLXXIII, CLXXIV, CLXXV, CLXXVI, CLXXVII, CLXXVIII, CLXXIX, CLXXXI, CLXXXII, CLXXXIII, CLXXXIV, CLXXXV, CLXXXVI, CLXXXVII, CLXXXVIII, CLXXXIX, CXC, CXCI, CXCII, CXCIII, CXCIV, CXCV, CXCVI, CXCVII, CXCVIII, CXCIX