Say someone has a speed of 35 feet and they are knocked prone:
On page 190 of the PHB it says under "Being Prone"
Standing up costs more effort; doing so costs an amount of movement equal to half your speed. For example, if your speed is 30 feet, you must spend 15 feet of movement to stand up.
This seems pretty straightforward and until now I have always assumed that you round down when you are done with all your calculations so in the example above you divide 35 by 2, which gets you 17.5. Then you do 35-17.5=17.5. Then you round down to the closest 5-foot increment, which gets us 15 feet of remaining movement.
But the wording on the rule is interesting because it suggests that it's more of a cost rather than a calculation (this part I struggle to articulate, I tried my best). The cost should be therefore 17.5 rounded down, which is 15. So the character should have 20 feet of movement after standing up.
Do you think my reading of it is supported by the text or have I thought myself into a corner here?
