this is something I learned in
high school, though I didn't believe until
college. It absolutely stumps some
people, but to others, it is pretty much
common sense.
one equals point nine repeating
The simplest explanation is that .999... goes on forever so there is no number between .999... and 1 therefore they are effectively the same number.
There are other, much more complicated proofs, so you are free to type one up...