> Mathematicians define equality of fractions by stating that a/b = c/d if and only if a·d = b·c. This means that if we define 1/0 = 1 then 0 = 1. That's not i

> Mathematicians define equality of fractions by stating that a/b = c/d if and only if a·d = b·c. This means that if we define 1/0 = 1 then 0 = 1. That's not implied, so far as I can tell. a / b = 1 / 0, thus a * d = b * c => 1 * d = 0 * c => d = 0 So all you can say is that d = 0, or at most that c / 0 = 0. Is there some extra step you're taking?