Il numero romano MMCMLXXX nel sistema decimale vale: 2980.
MMCMLXXX in latino si scrive duo milia nongenti octoginta,
mentre in italiano duemilanovecentottanta.
MMCMLXI, MMCMLXII, MMCMLXIII, MMCMLXIV, MMCMLXV, MMCMLXVI, MMCMLXVII, MMCMLXVIII, MMCMLXIX, MMCMLXX, MMCMLXXI, MMCMLXXII, MMCMLXXIII, MMCMLXXIV, MMCMLXXV, MMCMLXXVI, MMCMLXXVII, MMCMLXXVIII, MMCMLXXIX, MMCMLXXXI, MMCMLXXXII, MMCMLXXXIII, MMCMLXXXIV, MMCMLXXXV, MMCMLXXXVI, MMCMLXXXVII, MMCMLXXXVIII, MMCMLXXXIX, MMCMXC, MMCMXCI, MMCMXCII, MMCMXCIII, MMCMXCIV, MMCMXCV, MMCMXCVI, MMCMXCVII, MMCMXCVIII, MMCMXCIX