8

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

 

Summary

 

First column + Second Column

137174205 + 1097393685

 =

123456790

12345679 (There is no 8)

 

12345679, multiply with 9

12 345 679 x 9 == 111 111 111

12 345 679 x 18 == 222 222 222

12 345 679 x 27 == 333 333 333

12 345 679 x 36 == 444 444 444

12 345 679 x 45 == 555 555 555

12 345 679 x 54 == 666 666 666

12 345 679 x 63 == 777 777 777

12 345 679 x 72 == 888 888 888

12 345 679 x 81 == 999 999 999

12 345 679 x 999 999 999 == 12 345 678 987 654 321