So far I've busted three of these threads.

The Marko Rodan thread. (a few months ago)
The 3 6 9 thread. (today)
This thread. (today)

All similar, though Marko Rodan's thread required me to come up with a result involving multiplication of the digital roots so it was a little harder. I needed to get the result about addition first, then apply it iteratively to get the result about multiplication. Having done that thread, it was downhill from there.

And it continues downhill, now there's a guy here in this thread who is trying to argue in favor of dividing equations by zero. Whatever.

I hope someone else debunks the next one.