How to work out Hawklok pieces for a shed of a certain size (in feet)

If you have a 10’ by 8’ shed (only works in feet) you half each measurement so it would be 5’ x 4’ (round up to nearest figure if 5.5 it would be 6) times 5x4 = 20 which is how many pieces you need to make a 10 x 8 shed base with hawklok pieces.