How to calculate by what percent one number is greater or less than another?

Question

Mathematics

There is one number and there is another number.
Both or one of them can be zero, but they are never negative.
You need to calculate by what percentage one is more or less than the other.

Answer 1

1/0 = ∞
0/0 = uncertainty
Yes, I know that this is a mistake and only under the sign of the limit is such recklessness and rudeness allowed.
Either that, or throw an error.

Answer 2

the first number is x, the second is y (x > y) % =
100(x/y) - 100 1050 percent (80 over 40 over 100, 120 over 200, 160 over 300 ... 440 over 1000, 460 over 1050)