If there's one thing I've learned about math, it's that Sang-drax is always right.
What's the average of infinity and 12? You can't plug concepts like that into normal math equations. The idea of 0.999... is different from a specific number.
And certainly 0.999... is not equal to 1. Just because you can't find a number in between them doesn't make them the same. The inequality 0.999... < 1 still holds for any number of nines.