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

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

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

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