8E7A
      +---------
B7323 | A778C625
       -D6949
        =====
        BA9DB6
       -BD5E33
        ======
         B83542
        -BB4A41
         ======
           26125
          -3E745
           =====
            0A01

base: 15
letters: 0123456789ABCDE
difficulty: challenging
missing: 0