Il numero romano MDCXC nel sistema decimale vale: 1690.
MDCXC in latino si scrive mille sescenti nonaginta,
mentre in italiano milleseicentonovanta.
MDCLXXI, MDCLXXII, MDCLXXIII, MDCLXXIV, MDCLXXV, MDCLXXVI, MDCLXXVII, MDCLXXVIII, MDCLXXIX, MDCLXXX, MDCLXXXI, MDCLXXXII, MDCLXXXIII, MDCLXXXIV, MDCLXXXV, MDCLXXXVI, MDCLXXXVII, MDCLXXXVIII, MDCLXXXIX, MDCXCI, MDCXCII, MDCXCIII, MDCXCIV, MDCXCV, MDCXCVI, MDCXCVII, MDCXCVIII, MDCXCIX, MDCC, MDCCI, MDCCII, MDCCIII, MDCCIV, MDCCV, MDCCVI, MDCCVII, MDCCVIII, MDCCIX