@KZadBhat #78822
It's not even a matter of degree. If you are looking at .999... it is less than 1 if your definition of infinity is "unfathomably large number" in which case it terminates at an arbitrary point, albeit one outside of comprehension.
But thinking of infinity as a number isn't strictly correct. It's more of a process -one that continues indefinitely. But it still can be analyzed in a coherent way by thinking in terms of iteration.
1 - 0.9 = 0.1, 1 - 0.99 = 0.01, 1 - 0.999 = 0.001 and so on.
The difference between the two gets smaller and smaller. At infinity it isn't just "so close to 1 as to be indistinguishable". It's infinitely close to 1.