Answer:
Pictured this you have 3/4 of a sandwich and eat half of that 3/4 of the sandwich. you know have eaten 3/8 of a full sandwich and have 3/8 left.
if we were to actually divide 3/4 by 1/2 we would get 1.5 or 1 1/2 which would not make sense, so instead, we multiply and get 3/8