What does 55.845 round to?

Rounding a number, with no specific aim and without context, can often be a complete waste of time. It comes down to the context of what needs to be done with the number.

If I had to add 55.845 to 1 trillion, I would round it down to 0.
If I had to add 55.845 to 0.0000000001, I would use the number as given, or possibly 56.