When having a long rest, you regain all your hit points and half your spent Hit Dice (for use in future short rests). I know that normally when faced with fractions you round down. But then, I see no way to regain your 1 Hit Die at 1st level.
So basic question: if you are at first level, and you take a long rest, do you regain your Hit Die, or do you not because you had to halve 1 and round down?
The general rule is to round down, so you round down.
Unless you are told otherwise in the rules, D&D always mandates you round down. The Long rest section has no such exception (the only exception I've seen so far is for the wizard's spell recovery)
v.2 of BD&D now includes language that indicates a minimum of 1 HD is recovered during a long rest.
The character also regains spent Hit Dice, up to a number of dice equal to half of the character’s total number of them (minimum of one die). (p 67)
Fortunately the answer is quite simple. From the Basic Rules (still applies in PHB):
Round Down There's one more general rule you need to know at the outset. Whenever you divide a number in the game, round down if you end up with a fraction, even if the fraction is one-half or greater. ~ Basic Rules, p. 4
This should apply in all cases, except where it logically should not. The case you mention here would be a good example. Remember that it is very hard to make RAW consistent and synchronized at all times when it spans hundreds of pages. A bit of interpretation is often necessary.
