Gregory has $\frac{2}{3}$ of an entire pizza. If he gives $\frac{1}{4}$ of an entire pizza to his friend Marlene, what fraction of his partial pizza did he give to Marlene?
I'm not sure that I have interpreted your writing correctly, but:
If Gregory has 2/3 rds of an entire pizza and if he gives 1/4 th of an entire pizza to Marlene,
then he has given (1/4) / (2/3) = (1/4) · (3/2) = 3/8 of his partial pizza to Marlene.