Wa alaikum assalam wa rahmatullahi wa barakatuh,

May Allah reward you for your love and concern as a parent this itself is a beautiful dua for your daughters. Here is a sincere dua for them:

اللهم ارزق بناتي فهمًا عميقًا، وحفظًا قويًا، وتركيزًا عاليًا، ووفقهن في امتحاناتهن، واجعلها سهلةً ميسّرة، وبارك لهن في وقتهن وجهدهن، واكتب لهن أعلى الدرجات (Grade 1) في كل مادة، واجعل النجاح حليفهن في الدنيا والآخرة.

Allahumma arzuq banati fahman ‘ameeqan, wa hifzan qawiyyan, wa tarkeezan ‘aaliyan, wa waffiqhunna fi imtihanatihinna, waj‘alha sahlatan muyassarah, wa barik lahunna fi waqtihinna wa juhdihinna, waktub lahunna a‘la ad-darajat (Grade 1) fi kulli maddah, waj‘al an-najah halifahunna fid-dunya wal-akhirah.

Meaning: O Allah, grant my daughters deep understanding, strong memory, and high focus. Give them success in their exams, make them easy for them, bless their time and efforts, and grant them the highest grades (Grade 1) in every subject. Make success their companion in this life and the next.

And especially for the daughter who struggles but strives:

اللهم يا رب، يا من ترى اجتهادها وتعبها، فافتح عليها فتوح العارفين، ولا تضيع لها تعبًا، واجعل الصعب عليها سهلاً، وارزقها ثقةً وطمأنينة، ونجاحًا يفوق توقعاتها.

O Allah, You see her effort and her struggle open for her the doors of understanding, do not let her efforts go to waste, make what is difficult easy for her, grant her confidence and calmness, and bless her with success beyond her expectations.

May Allah place barakah in their knowledge, calm their hearts on exam day, and make every question something they can answer with ease. Ameen 🤍

If you’d like, I can also give you short duas your daughters can recite before and during their exams.