let x = 0.3636363636…
then 100x = 36.363636…
Subtract the two from each other you get
100x - x = 36.363636… - 0.363636…
Notice that the repeating 36s line up perfectly and will subtract out to exactly 0/
99x = 36 : Divide both sides by 99
x = 36/99 : Divide out the common 9 in both the numerator and the denominator
x = 4/11
