Unless you've stored those un-rounded values in a variable that still exists, you can't.
Suppose I tell you I bought two items A and B from the store, and that their prices (rounded to the nearest dollar) are each $3. Is item A or item B more expensive? With just the information I gave you that question is impossible to answer. You'd need something else, like a peek at my receipt (which would have the original prices, and in this case would correspond to having a backup copy of the original data in a separate variable) to answer that question.
