>What's the best way to store numbers like 2/3, but in situations where you
>do not want to do any rounding at all. Do you store 2/3 as a string?

If you mean to store general fractions, I agree with Fabio, best thing to do is to store two integers. Maybe add some code to divide both with the largest common divider first. You may even write some code to do basic integer arithmetic with them - adding and multiplication. Depends on what do you want to do with them down the road.