Interesting bit of math I learned

.6666 equals 1.

0.99999... = lim_{n->\infty} \sum_{m=1}^n 9*10^{-m}
  = lim_{n->\infty} (1 - 10^{-n})
  = 1 - lim_{n->\infty} 10^{-n}
  = 1 - 0
  = 1

If we don't answer with proof, then the trolls win.