Il numero romano MCM nel sistema decimale vale: 1900.
MCM in latino si scrive mille nongenti,
mentre in italiano millenovecento.
MDCCCLXXXI, MDCCCLXXXII, MDCCCLXXXIII, MDCCCLXXXIV, MDCCCLXXXV, MDCCCLXXXVI, MDCCCLXXXVII, MDCCCLXXXVIII, MDCCCLXXXIX, MDCCCXC, MDCCCXCI, MDCCCXCII, MDCCCXCIII, MDCCCXCIV, MDCCCXCV, MDCCCXCVI, MDCCCXCVII, MDCCCXCVIII, MDCCCXCIX, MCMI, MCMII, MCMIII, MCMIV, MCMV, MCMVI, MCMVII, MCMVIII, MCMIX, MCMX, MCMXI, MCMXII, MCMXIII, MCMXIV, MCMXV, MCMXVI, MCMXVII, MCMXVIII, MCMXIX