How to convert a repeating decimal to a fraction

Always place it out of 9. For example, 0.333 = 3/9, or if simplified, 1/3.

0.5555? this will be 5/9.

for the other way around, make it a repeating decimal, such as 4/9, make that 0.444

If it is 33/99, or even 333/999, the rule should be the same.