I was wandering if someone could tell me how I could make c# do a round off for 1/3 or 2/3 before placing it into a calculation.

For example:

I know that c# is terrible with 1/3 and 2/3 and will output an incorrect value if put into an equation... (Ex. (a * (2/3) * (2/3))+(b*(1/3)+c)) cause i have tested..

So, i decided that since 1/3 and 2/3 are infinite decimals (0.333...and so on) i was wandering if someone could tell me how to tell c# to round off 1/3 or 2/3 (0.33) before putting it into the calculation.

Any ideas?