I believe the number to be converted to a fraction is 0.232323..., this is 0.23 periodic.
The formula is right:
Where is 0.23 and r is 1/100
Check it here:
23/100 23/100 23
-------------- = ----------- = ------- = 0.232323...
1 - 1/100 99/100 99
So, the answer is 23/100 and r = 1/100