> If someone sells you 12345.55 EUR vs USD at a rate of 1.12345, how many EUR do you think you end up with?

1. If someone sells me 12345.55 EUR, I hope to end up with 12345.55 EUR.

2. That's the point though. They will sell you a certain amount of EUR at a certain dollar price. This, in turn, implies a rate (which might well have more than 5 digits behind the decimal). This is ideally close to the quoted rate, sure. But what counts is the actual EUR amount and the actual USD amount, not what rate was quoted or with how many digits.