Let's try it with the first few guys we did:

x^5 / x^2 = x^(5-2) = x^3

y^8 / y^3 = y^(8-3) = y^5


So far, no problem!

What about this guy?

w^3 / w^5 = w^(3-5) = w^(-2)

I haven't even told you about negative exponents yet...
And, even when I do, they're something we'll want to avoid.

So, do these critters with your brain, not with the rule!