easier way

You can also see that 8 x 10^k will always have a remainder of 8 when divided by 9. That is, 8 x 10^1 = 80, which has a remainder of 8 when divided by 9. 8 x 10^2 = 800 which also has a remainder of 8 when divided by 9. . . . etc. Therefore, the only variable we need to concern ourselves with is wha...