# Question in math ..do you belive 1+1 = ?

my friend has convinced me that 1+1 = 1.99..

not to 2 exactley by this solution

http://www.m5zn.com/uploads/2011/6/18/photo/061811...

so what do you think ? how can I tell her that her solution has sth that not accurate cause I am still not convince really but couldn't find any mistakes since I am not fully aware of the equations that she used..

what does the bar mean above 99 ???

### 4 Answers

- Anonymous9 years agoFavorite Answer
This is true. There are many ways of proving that 1=.99...

This equation is simply an application of that.

For another proof of this (hopefully you are familiar with geometric series).

.9999...=9/10+9/100+9/1000+....

This is an infinite geometric series, whose sum is (9/10)/(1-1/10)=1.

So, we established that .99...=1.

There are no flaws in your friend's solution.

For more on this discussion, see http://www.artofproblemsolving.com/Forum/viewtopic...

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- MorningfoxLv 79 years ago
Actually, the link you posted has 1 + 1 = 1.99...(repeated 9's). It seems to leave out a few repeat signs in some of the equations.

And it is correct. However, an easier way to write 1.99...(repeated 9's) is just plain old "2".

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- Anonymous9 years ago
It can't be. The equation isn't accurate. It's like x= 4 and so 4=6. Which isn't true. 1=1 and 0.99=0.99

And even the result is wrong. 0.99+0.99 are 1.98. The worlds greatest mathematicians would have found that out and I didn't find anything on the web.

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