有趣的数学公式

        1 * 8 + 1 = 9
       12 * 8 + 2 = 98
      123 * 8 + 3 = 987
     1234 * 8 + 4 = 9876
    12345 * 8 + 5 = 98765
   123456 * 8 + 6 = 987654
  1234567 * 8 + 7 = 9876543
 12345678 * 8 + 8 = 98765432
123456789 * 8 + 9 = 987654321