Jim is a halfling rogue with two levels of exhaustion. This means that their base speed is 25 ft., and that their current speed is halved to 12.5 ft.
Now imagine that Jim uses their movement to move, their action to Dash and their Cunning Action to Dash, all in a straight line.
How far can Jim run? Is it 12.5 ft. rounded down to 10 ft. times 3 = 30 ft.? Or is it 3 times 12.5 = 37.5, rounded down to 35 ft.?
Best Answer
Jim can move 36 feet, or 35 feet (7 squares) if using the variant grid rules.
First, the rounding rule:
So half-speed for Jim is 12.5 feet, rounded down, giving a speed of 12 feet. The rules for movement state:
Jim's speed is 12, so he can move 12 feet with his usual move, and an additional 12 feet for each Dash, resulting in a total of 36 feet with his two available Dashes.
Using a grid is a variant rule.
Moving 5 feet at a time is not the standard rule for D&D, it is actually an optional rule, under the heading "VARIANT: PLAYING ON A GRID". When playing on a grid, you use your movement in 5 foot blocks:
So with his usual move, having a speed of 12 translates to 10 feet of movement:
After using 10 feet (2 squares), Jim has 2 feet of movement left. You do not round a 12 feet speed down to 10 feet. You just have 2 feet of movement remaining after moving 10, which is not enough to enter a new square. Dashing twice adds 24 feet to his available movement, so he would have 26 feet of movement remaining, or 5 squares, which gives a total movement on the turn of 35 feet (7 squares.