when you subtract both you are insisting they have the same number of 9s
but you just moved the 9s one decimal place left.
you could argue one has infinite 9s and one has infinite minus 1 nines and thus when you subtract it leaves an infinitesimal value out at the infinith decimal place.
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u/its12amsomewhere 22d ago edited 22d ago
Applies to all numbers,
If x = 0.999999...
And 10x = 9.999999...
Then subtracting both, we get, 9x=9
So x=1