6ABF
      +---------
BC1D9 | 84DF4DDE
       -BC1D9
        =====
        31FC9D
       -3F8C53
        ======
         E17F2D
        -E2043D
         ======
          63E97E
         - 975E4
          ======
           1E683

base: 16
letters: 0123456789ABCDEF
difficulty: medium
missing: A