If you want to debate logic and theory, rant away people have been doing so forever, if you want to pass physics and trig, adhere to the afformentioned.
If thats just a riddle or clever concept, then uhh hardy har?
"There is a logic flaw here. By definition, a infinite number is, uh, infinite. By multiplying it, you end up with another infinite number, that is, 9.9999... (repeating forever)."
You cannot mulitply it because you cannot understand it well enough to factor, which is why when working with numbers you cannot calculate, you round it, or you exchange with a variable. One way is accurate, one way is precise.
"i highly doubt his teacher will think this is correct also..."
If they "ventured" about it in class, I'm pretty sure the teacher is included.
And if the teacher knew about it and was just trying to make the students think, which is more than possible if not likely as the good teachers make you think instead of just telling it like it is all day, then yeah that would be a good thing. Otherwise, yeah thats sad for someone with a degree.
"how do you prove Tiggz wrong???"
You don't, he's right =p
If you really just want some puzzling concept, try to understand how infinity works. In the most simple form positively, you just think, no matter how big something is, you can make it bigger.
In a negative form, no matter how small or microscopic something is, you can cut it in half.
So if I'm walking to a door, and the space between my hand the the doorknob can keep being cut in half infinetly, how can I ever reach it?