Yesterday i was puzzling with some problems related to fractions ,for example:-
**Find out the coprime possitive integers (a,b) such that when a is divided by b yields the fraction 0..688888888.......**
Problem can be easily solved as follows:-
\[let x=0.68888888888....-(1)\]
Multiplying both sides by 100:-
\[100x=68.88888888.....-(2)\]
Subtracting equation one from equation two:-
\[99x=68.2\]
On canceling comen divisers:-
\[x=\frac{31}{45}\]
Since 31 and 45 are coprime so answer is (31,45)
Mathod can be used to convert all rational fractions into the form \[\frac{a}{b}\]
After solving five or six such problems by using this mathod i tried to convert 0.99999999.... into the form a÷b but got a contradiction as follows:-
\[let x=0.999999...........-(1)\]
Multiplying both sides by 10:-
\[10x=9.99999999.......-(2)\]
Subtracting (1) from (2):-
\[9x=9 ==> x=1\]
But from equation (1) x=0.99999.....
So does this means that 0.99999....=1
.
.
Well i think this could be probebly because 0.99999.... is an irrational number (i think so),but problem is that i am not much fimiler with mumber theory so i don't know any mathod to prove that this number is irrational...what do you think about it..

Sorry for all grammer and spelling mistakes i am not good in english :p

## Comments

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TopNewesthard works makes man perfect – Ram Charan · 2 years, 3 months ago

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Anytime you have a repeating decimal, it's a rational number. So, 0.9999999.... etc is pretty rational to me.

Another example:

\(0.05882352941176470588235294117647058823529....\)

looks irrational, but it actually repeats (look CAREFULLY). This one is \(1/17\). – Michael Mendrin · 2 years, 10 months ago

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aandbsuch that a/b=0.99999........ I also tried to solve it by converting number into infinite series but in vainAlso number given by you is aldo rational i solved it by mathod of differences – Aman Sharma · 2 years, 10 months ago

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See.. no. Is irrational only when it is neither recurring nor repeating....like

.99999999 or .12367456456456

so both these no. Are rational and can be convert into a:b... – Rishabh Neekhara · 2 years, 10 months ago

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– Aman Sharma · 2 years, 10 months ago

Can you convert 0.99999......... into a:bLog in to reply