Precision clarification

I've been using the lib with a precision of 34, and I've noticed that when using `Text()`, some of my decimals terminate with `...9999999` or `..0000001`. I suspect it's got something to do with [this](https://github.com/cockroachdb/apd/blob/v2.0.2/format.go#L25).

Is there a way I can avoid having such errors, because my PoC app requires a certain sum total to be exactly zero, even at the precision of 34, which I can't achieve with such errors. I have to use `f` and can't use scientific notation. I'd like to know why this error occurs, and why it can't be fixed, because I've noticed the shopspring lib having a similar problem.