begin by letting x = 0.5555555................. (1)
To obtain the same repeating part after the decimal point need to multiply by 10
hence 10x = 5.555555........................(2)
It is important to obtain 2 equations in x, where the recurring part after the decimal points are exactly the same.
now subtract (1) from (2) to obtain fraction
(2) - (1) : 9x=5⇒x=59