In order to determine the rest of miles Michael has to run, subtract 11/4 to 20/4, as follow:
20/4 - 11/4 = (20 - 11)/4 = 9/4
where it has been taken into account the fractions are homogeneus, tha is, they are subtracted by subtracting the numerators and the denomiantor is the same to both fractions.
Hence, Michael has to run 9/4 miles.
