數學也能讓你驚訝地笑一笑

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

        0 x 9 + 1 = 1
        1 x 9 + 2 = 11
       12 x 9 + 3 = 111
      123 x 9 + 4 = 1111
     1234 x 9 + 5 = 11111
    12345 x 9 + 6 = 111111
   123456 x 9 + 7 = 1111111
  1234567 x 9 + 8 = 11111111
 12345678 x 9 + 9 = 111111111
123456789 x 9 + 10= 1111111111

       9 x 9 + 7 = 88
      98 x 9 + 6 = 888
     987 x 9 + 5 = 8888
    9876 x 9 + 4 = 88888
   98765 x 9 + 3 = 888888
  987654 x 9 + 2 = 8888888
 9876543 x 9 + 1 = 88888888
98765432 x 9 + 0 = 888888888


        1 x 1 = 1
       11 x 11 = 121
      111 x 111 = 12321
     1111 x 1111 = 1234321
    11111 x 11111 = 123454321
   111111 x 111111 = 12345654321
  1111111 x 1111111 = 1234567654321
 11111111 x 11111111 = 123456787654321
111111111 x 111111111 = 12345678987654321