8. An apple pie was cut into 8 slices. Sally ate 1 slice and Jim ate 3 slices. How many slices did they eat together? What portion of the pie is that?

This is a fine addition problem, the only thing wrong with it is it doesn't have a significant use of fractions. Instead of it being natural to add 3/8 and 1/8, it is natural to add 1+3 and then make the fraction. I gave half credit to the student who wrote this problem. This problem could be fixed by giving the amounts as fractions:

Fixed: Sally ate 1/8 of an apple pie and Jim ate 3/8 of the pie. How much of the pie did they eat together?