0B23
      +---------
A3D19 | 5C09D183
       -A3D19
        =====
        0A3C81
       -061AE2
        ======
         3A3388
        -3B27CB
         ======
          05C513
         -0538E5
          ======
            536E

base: 15
letters: 0123456789ABCDE
difficulty: hard
missing: 4