Gacha Gacha Next Revolution Graphic Novel Volume 10 (Mature)

"(W/A) Hiroyuki Tamakoshi Akira will flunk out unless he can ace his math exam. The problem is, he's hopeless with numbers. Luckily, math wiz Yurika and her cute sister, Anju, offer to help Akira study. For motivation, the girls give Akira positive reinforcement every time he gets a problem right. The rewards start out small, but soon he has the girls feeding him cake, changing into their swimsuits, and hugging and squeezing him. With incentives like these, Akira could turn into the next Einstein!"