What is the ruling on supplicating with the words: "O Allah, I entrust to You what I have memorized, so return it to me when needed," to aid in exams?

There is no harm in the supplication "I entrust you to Allah" because when something is entrusted to Allah, He preserves it. The supplicant should ask Allah to preserve what has been entrusted to Him and to return it when needed. It has been reported that Luqman al-Hakim said: "Indeed, Allah, the Most High, when something is entrusted to Him, He preserves it." The Prophet, peace and blessings be upon him, used to bid farewell to a traveler by saying: "I entrust to Allah your religion, your trust, and the last of your deeds."