mysevenkids replied to your post:

*thishedgehog replied to your chat: Kidbro: [18 x 4…*9s count up in the 10s column while they count down in the 1s column, and the 10s column is one less than you’re multiplying 9 by plus the 2 digits add up to 9 (9x2=18, 9x4=36, etc).also if the digits of any number add up to a number divisible by 9, the entire number is divisible by 9.

Oh, that last one is *interesting*, is there a proof for it?