Quote:
Originally Posted by Polar Bear
Seems like if you took it one number further, what you say doesn’t add up.
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Woah, I just extended it to check - gonna have to call my dad and tell him he was wrong!
However - the left-to-right column addup is still valid. All digits in multiples of nine, when added left to right, will always equal when you keep adding until there's one digit left. (so 9*11 = 99, 9+9=18, 1+8=9)