The median is the middle of the list when the list is sorted. 6,10,11,13,14,14,20,20,23,23,26,27,31,33,38,38 This is the sorted list, so we count evenly up and down the list. In this case, there are 16 total numbers, meaning we count 8 up and 8 down, arriving at 20,23 with the middle being in between them. Both of them can't be the median, so we take the average of these two numbers, which is 21.5. So, the median 21.5.
In order to add or subtract fractions, the denominators need to be the same. In this case, the lowest common denominator would be 15abc.
So to get to that, you'll end up with 20abc/15abc - 45abc/15abc. Now you can subtract the numerators, which will give you -25abc/15abc. Once divided and simplified, your answer will be -5/3.