3419
      +---------
25509 | 70764B02
       -25509
        =====
        A8957B
       -A3511C
        ======
         A38070
        -0BC783
         ======
          281232
         -8C3B28
          ======
           28773

base: 13
letters: 0123456789ABC
difficulty: intermediate
restrictions: no multiplication