4 ms·

I find the algebraic way convinces most people: x = 0.9999.. 10x = 9.9999... 10x - x = 9 9x = 9 x = 1

• solotronics 6y ago
  black magic! I wonder if there are any programming languages that are able to handle this properly?
  • 2OEH8eoCRo0 6y ago
    https://www.wolframalpha.com/input/?i=.9...+%3D+1 https://www.wolframalpha.com/input/?i=.9...+%3D+1
    • tygrak 6y ago
      https://www.wolframalpha.com/input/?i=10*0.9...-0.9.. https://www.wolframalpha.com/input/?i=10*0.9...-0.9...
  • brlewis 6y ago
    There are programming languages with rational number types, but none that I know of that represent numbers as repeating decimals.
• taylodl 6y ago
  That's how I was taught in my Algebra class
• thenewwazoo 6y ago
  Because I wondered, it’s not a trick: x = 0.444444... 10x = 4.444444... 10x - x = 4 9x = 4 x = 4/9 = 0.444444...
  • phaemon 6y ago
    All the single digit repeating decimals are x/9. 0.111... == 1/9 0.222... == 2/9 ... 0.888... == 8/9 0.999... == 9/9 :)
• sethammons 6y ago
  I was prepared to blow my then 6th or 7th grade daughter's mind with this algebraic proof. I started by asking if 0.999... = 1, to which she said "no." I rephrased it and said it is equal, do you know why? She thought for a moment and said "1/9 is 0.111..., so 9/9 is 0.999... and 9/9 is 1." And I had to admit she had a far better solution than I did.