In order to compute the substraction, we must convert the mixed fractions into a simple fraction form.
For the first fraction, we get

similarly, for the second fraction, we have

Now, the subtraction can be computed and is given by

then, we must find the common denominator. We can note that 8*5=40, then this substraction is
then, the substraction is

and the resul is

Now, we must convert this simple fraction into a mixed fraction form again. It gives
