In math we started on infinitesimal calculus this year, and there we often divide by zero, which gives infinity. And similarly dividing by infinity gives 0.
According to Wikipedia, you can't do it normally, but only in infinitesimal calculus.
http://en.wikipedia.org/wiki/Division_by_0Which makes no sense to me logically. Maybe because you just don't want infinites normally.
But logically a number divided by 0 should give infinity, as the smaller the number you divide it by, the greater the number becomes.
Our teacher wrote this example on the blackboard. Dividing by negative zero becomes negative infinity, dividing by zero becomes positive infinity. Kol.
Ask your teacher about infinitesimal calculus.