/prog/rammer here, need urgent help

hello /sci/, long time no see
There is currently a troll on /prog/, and would greatly appreciate your help.

Basically, the troll is trying to prove that 0.999~ =/= 1
Here are some of his arguments
http://stormtower.invisionplus.net/?mforum=stormtower&showtopic=97

I'm wondering if the maths genius' on this board can rip him apart? Thank you

>>12
My question to you is, what have you contributed to this big field of maths? What was the last big contribution from maths which literally changed the way we live? You mathematicians remind me of the 80 year old baseballer, once famous in his day but now too old and decrepit to be doing anything useful. Instead, this old fart likes to remind people of how good he once was, instead of... you know, letting nature take its course and dying.
Face it gramps, you're finished. I would estimate 80% of maths graduates either change majors, or go off to become sales assistants or coal miners.
Face it, you're our janitorial offspring.
I find this statement particularly interesting. Janitorial offspring, how quaint. You know, I couldn't agree more. We run the show now, pops. We create the software for the GPS in your car, the OS and software you use at home.
We quite literally rule the world.

>>14
Blah blah blah. I don't care about what those old farts did 500 years ago. Tell me, what are you contributing to the world right now, with your maths degree? What are you researching? What are you doing with your life?