Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Lower and Upper bound proof in R

  1. Mar 7, 2013 #1
    I am getting lost in the proof in the 5th line when it says there are 10 numbers that have the same kth digit as x. Why 10? I don't understand where this number is coming from and it doesn't seem arbitrary.

    the rest of the proof
  2. jcsd
  3. Mar 7, 2013 #2


    User Avatar
    Science Advisor

    From the fact that the decimal expression is in base 10.
    Walk through the proof with a specific example.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook