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

* * * * *

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 X9 + 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