Il numero romano MMMCMLXXX nel sistema decimale vale: 3980.
MMMCMLXXX in latino si scrive tria milia nongenti octoginta,
mentre in italiano tremilanovecentottanta.
MMMCMLXI, MMMCMLXII, MMMCMLXIII, MMMCMLXIV, MMMCMLXV, MMMCMLXVI, MMMCMLXVII, MMMCMLXVIII, MMMCMLXIX, MMMCMLXX, MMMCMLXXI, MMMCMLXXII, MMMCMLXXIII, MMMCMLXXIV, MMMCMLXXV, MMMCMLXXVI, MMMCMLXXVII, MMMCMLXXVIII, MMMCMLXXIX, MMMCMLXXXI, MMMCMLXXXII, MMMCMLXXXIII, MMMCMLXXXIV, MMMCMLXXXV, MMMCMLXXXVI, MMMCMLXXXVII, MMMCMLXXXVIII, MMMCMLXXXIX, MMMCMXC, MMMCMXCI, MMMCMXCII, MMMCMXCIII, MMMCMXCIV, MMMCMXCV, MMMCMXCVI, MMMCMXCVII, MMMCMXCVIII, MMMCMXCIX