This question already has an answer here:
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?