Il numero romano CDIII nel sistema decimale vale: 403.
CDIII in latino si scrive quadringenti tres,
mentre in italiano quattrocentotré.
CCCLXXXIV, CCCLXXXV, CCCLXXXVI, CCCLXXXVII, CCCLXXXVIII, CCCLXXXIX, CCCXC, CCCXCI, CCCXCII, CCCXCIII, CCCXCIV, CCCXCV, CCCXCVI, CCCXCVII, CCCXCVIII, CCCXCIX, CD, CDI, CDII, CDIV, CDV, CDVI, CDVII, CDVIII, CDIX, CDX, CDXI, CDXII, CDXIII, CDXIV, CDXV, CDXVI, CDXVII, CDXVIII, CDXIX, CDXX, CDXXI, CDXXII