Il numero romano CCCLXXVIII nel sistema decimale vale: 378.
CCCLXXVIII in latino si scrive trecenti septuaginta octo,
mentre in italiano trecentosettantotto.
CCCLIX, CCCLX, CCCLXI, CCCLXII, CCCLXIII, CCCLXIV, CCCLXV, CCCLXVI, CCCLXVII, CCCLXVIII, CCCLXIX, CCCLXX, CCCLXXI, CCCLXXII, CCCLXXIII, CCCLXXIV, CCCLXXV, CCCLXXVI, CCCLXXVII, CCCLXXIX, CCCLXXX, CCCLXXXI, CCCLXXXII, CCCLXXXIII, CCCLXXXIV, CCCLXXXV, CCCLXXXVI, CCCLXXXVII, CCCLXXXVIII, CCCLXXXIX, CCCXC, CCCXCI, CCCXCII, CCCXCIII, CCCXCIV, CCCXCV, CCCXCVI, CCCXCVII