http://en.wikipedia.org/wiki/Interval_arithmetic
We currently have a huge over tolerancing problem. We don't need exact math most of the time.
http://web.media.mit.edu/~bates/Summary_files/BatesTalk.pdf
You can't simulate a brain accurately (and you probably don't need to). Neurons aren't very accurate themselves, and it does the job fine.
http://en.wikipedia.org/wiki/Interval_arithmetic
We currently have a huge over tolerancing problem. We don't need exact math most of the time.
http://web.media.mit.edu/~bates/Summary_files/BatesTalk.pdf