Mathematical

1x8+1 = 9
12x8+2 = 98
123x8+3 = 987
1234x8+4 = 9876
12345x8+5 = 98765
123456x8+6 = 987654
1234567x8+7 = 9876543
12345678x8+8 = 98765432
123456789x8+9 = 987654321
1x9+2 = 11
12x9+3 = 111
123x9+4 = 1111
1234x9+5 = 11111
12345x9+6 = 111111
123456x9+7 = 1111111
1234567x9+8 = 11111111
12345678x9+9 = 111111111
123456789x9+10 = 1111111111
9x9+7 = 88
98x9+6 = 888
987x9+5 = 8888
9876x9+4 = 88888
98765x9+3 = 888888
987654x9+2 = 8888888
9876543x9+1 = 88888888
98765432x9+0 = 888888888
1x1 = 1
11x11 = 121
111x111 = 12321
1111x1111 = 1234321
11111x11111 = 123454321
111111x111111 = 12345654321
1111111x1111111 = 1234567654321
11111111x11111111 = 123456787654321
111111111x111111111 = 12345678987654321