I've got a non-calc paper coming up, and when going through a test, this fraction came up:

$$ \frac{8}{-0.4} \equiv \frac{8}{\big(\frac{-2}{5}\big)} $$

Going through the answers he says: $$8/2=4$$ I then assume he did -(4*5) so: $$\frac{8}{\big(\frac{-2}{5}\big)} = -20$$

I can see what he's done, but I don't see what's happening mathematically?

$$\frac{a}{\frac{b}{c}} \equiv \frac{a}{b}\cdot c$$