Answer:
You take the repeating group of digits and divide it by the same number of digits but formed only by 9s.
Step-by-step explanation:
Let's say you have 0.111111111111...., your repeating pattern is 1, that consists of one digit (1). You take that digit and you divide it by 9:
1/9 is the fraction equivalent to 0.111111111111111...
Let's say you have 0.12121212121212...., the repeating pattern is 12, that consists of 2 digits (12). You take those 2 digits and divide them by 99:
12/99 is the fraction equivalent to 0.12121212121212...
which can be reduced to 4/33
If you have 0.363363363363..., your repeating pattern is 363, which is 3 digits, so you divide 363by 999:
363/999 is the fraction equivalent to 0.363363363363...
which can be simplified to 121/333