First of all, Ed ate 3/8 of the pizza and jen ate 1/4 of the pizza which means that they are total 3/8+1/4=3/8+2/8=5/8 of the pizzas. Also, we know the pizza has portion of 1 or 8/8 in this case, so 8/8-5/8=3/8 represent the portion of pizza is left. As a result, the pizza is 3/8 left. Hope it help!