If you want to learn other times where 0/0 = 1, this is a major part of limits in calculus. There is something called a sinc function in math where:

sinc(x) = sin(x) / x

Since sin(0) = 0, sinc(0) = 0/0, and if you plot this the answer is clearly 1. This is because the result is approaching 1 from both sides, but it's not always the case that this is true for every function that evaluates to 0/0. This is called L'Hôpital's rule in calculus.

Sincs appear a lot in physics, from the pattern made during the double slit experiment, fourier transforms, and are part of the explaination of Heisenberg's Uncertainity Principle.

So anyway, 0/0 = 1 is not always true, but it can be, as it's kinda the basis of calculus in a way.