Different ways to prove that .999... = 1
by Mark Frauenfelder from on (#2J8RG)
In 2012, Vi Hart made this video giving "9.999... reasons that .999... = 1" She also made a video of bad proofs why .999... does not equal 1.https://youtu.be/wsOXvQn3JuE
There's some interesting discussion about it at TYWKIWDBI.