Does .9 repeating = 1?

A friend told me it did, another told me it didn't. I say it doesn't, but I not sure considering both sides brought good evidence.

Thoughts?

you mean 0.999999999...=1 ? true

1/9=0.1111111...
2/9=0.2222222...
.
.
.
8/9=0.8888888...
9/9=0.9999999... and oviously 9/9=1

you can say 1=9/9=9*1/9=9*0.1111111111...

If your question is indeed "is 0.999...=1?" then the answer is yes. See Wikipedia for a few proofs:
en.wikipedia.org/wiki/0.999...

there cant be an evidence against. what did your friend tell you?

the mathematical idea you are looking for is called convergence and divergence. the idea is that 0.9 repeating can be as close to 1 as you want it to be. it then steps out of theory and into engineering and the question becomes, how close does this number need to be to 1 in order for our model to function properly, tolerance, margin of error, error coefficeient. the friend who told you that 0.9 repeating is equal to one has either studied math, or got his answer from someone who has. the other friend answered the question explicitly. both are correct.

to post # three, while it may not look like it from your post, what you did was continiously add 1/9, however on the last one, you forgot to carry the remainder.

#6 no!
firstly: you dont need to study math for this. i learned this in school.
secondly: you are wrong! 0.99999999...=1, nothing else.

another proof:
x=0.999...
10x=9.999...
10x=9+x
9x=9
x=1

what "remainder" are you talking about, #7??

there a are some strange things happening when infinite numbers are appearing. if you are interested in such things like hilberts hotel. or you can ask yourself the tricky question wich numbers are more: the natural or the rational.