ANSWER:
6_34/99
STEP:
So yes. When a decimal is repeating, you can take the repeating number (most likely a decimal) and put 99 under it. Since 99 cannot be solved, you put 99. So, 34/99. Though we are not finished. There is still the whole 6 number left. So, you do 6_34/99.
Proof:
10x=6.6...
-x=-0.6...
9x=6
x=6/9=1/3.