Wow, "different people with different opinions and different motivation". I think I have learned some thing about life:D
You are so nice. Since I didn't focus myself on coding until this year, what you said make me think a lot about coding. Coding should be a way to relax myself, instead of just making money.
Cause my English is really poor,there are many things I don't know how to express...Whatever, thank you for telling me these things. LOL

Yes, surely a good reason so nothing to say against;-)... But here are different people with different opinions and different motivation, sometimes with good and sometimes with bad days, so not always everything is perfect:-)... You will see the longer you are here (and it is as everywhere). But generally everything is ok i think, sometimes with small exceptions... So always "keep smiling", it's not a job and without money, but surely a good practice;-)...

I'm an intern. And my leader told me : Never write any dirty but work code...That's why I come here to practice:D

Perhaps next time you find a better one... sometimes (not very often) i do such "dirty but really harmless things":-)... perhaps you will see: sometimes it's part of this game here too;-)

https://docs.python.org/2/tutorial/floatingpoint.html
I don't know if the kata is to make 0.005 as its difficulty. LOL
Anyway, it doesn't that matter.:P

Yes, you are right, so normally the solution should be without "0.00005".
But (the time i did it) there was a wrong example- testcase, so to pass example tests and submit tests this correction was necessary. I often complete katas on early stage, so sometimes my solutions get invalid because of testcase- changes and i often do no second try. This solution is already accepted, but normally wrong;-)... But only a little little bit, exactly 0.00005...:-)!

Well... nothing...

I don't think it's correct.
For example, 2.67499995 will get 2.68, while the answer should be 2.67.

See here: http://jsfiddle.net/J3Spt/
Maybe it's not much shorter, but at least it's algoritmic :-)

toLowerCase() is useful, but the "charCodeAt()" cannot return a prime number.Any other way to shorten the length?

:-) You could replace your function num with:
num_code_of_x = x.toLowerCase().charCodeAt(0);