Mind Teasers : Is This Proof Correct Problem

Difficulty Popularity

p = 9.999999...
10p = 99.999999...
10p - p = 90
9p = 90
p = 10

In the proof above, you can find out how 10 is equal to 9.999999... .

Is this proof correct?

Does 10 equals 9.99999 for real or there is some error in the proof?

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