Mathematical function for weighting football results Let's assume team A has scored x goals, and team B has scored y goals in a match.
I'm trying to find a function that returns a number between 0 and 1 based on the goals from the match.
Ideally, the function would reach 1 when y is 0 and x approaches infinity.
I have a very simple function that works almost entirely as desired, and that is x/(x+y).
The problem with this function is that 1-0 gives the same function output as 10-0, 1.

If you are willing to make it more difficult to compute by hand, I would recommend a logistic function. Logistic functions will give you a very nice curve which, for probability purposes, is often better. A logistic curve could take a form like this:
$$ \dfrac{1}{1+e^{-k(x-y)}} $$ you could vary $k$ based upon how quickly you wanted the function to approach $1$. This will approach $0$ when $y$ is much larger than $x$, and will be $\frac{1}{2}$ when $y=x$
