We know 0.000...0001=0 because 9.999...=1 and 1-1=0, but 1-9.999... is clearly 0.000...0001. To multiply by a decimal like 0.000...0001, you simply treat it as if it were a whole number, in this case one. So let's say we divide three by zero.
3/1=3
Now that you've divided, just move the answer by the same number of decimal places as your last answer. Since we moved one an infinate nmber of places, we move 3 by an infinate number of places. Therefore anything divided by zero is equal to infinity. Except 0, which is one. And negaive numbers, which I guess would be negative infinity.