I know this will sound like a silly question but, have you tried NOT rounding the number? You're probably using int() to convert from text or something.
If you want a specific number of decimal places rather than all of them (which is a lot) the formula is round(Num*N)/N, where N is 1 followed by a number of zeroes equal to the numberof decimal places you want to keep (1 for no decimal places, 10 for 1 decimal place, 100 for 2 decimal places, etc)