The Quintessential Quintuplets volume 5 - Negi Haruba

 The story continues of the poor tutor having to try and get five sisters through their exams...

And it picks up with Futaro still in hospital, with the quintuplets father actually paying the bill.

The quintuplets come to visit him as they are in the hospital for their immunisation shots, and he unknowingly gets a compliment from their father.  When Itsuki visits him, he starts getting the feeling that the girl he met and fell in love with all those years ago, and whom made him change his life for the better, might actually have been one of them.

Back at their place, he tries to figure out who had 0's in their tests, only to deduct they all failed on certain subjects.  He decides though to take Yotsuba out on a "date" as thanks for all the effort and help she provided him with at camp.  After a whole day, he asks her what she actually wants for herself, and they end up at a swing in a park, where the view in the evening is breathtaking.

But then study has to pick up in earnest again, as there is only a week left to the exams.  But an argument between the sisters heats up so hard, both Nino and Itsuki decide to leave the house.  While Nino goes to a hotel, Itsuki bunks down at Futaro's place, and he learns from her that before their mother remarried their current father, they actually lived in poverty as well because as a single mom she had to take care of everything, at the cost of her own health in the process.

The manga also has some small chapters that didn't go in the anime, like one where they had to babysit Ichika's agents babygirl, playing mommy and daddy much to the joy of Miku.  So another cuteness dripping volume, time to hop to the next book!