Fujisan to Coffee to Shiawase no Sushiki

After his grandfather passes away, college student Takuma moves in with his grandmother Fumiko, who was left alone after her husband passed away. One day, Takuma finds a university admissions guide in the study of his late grandfather, Eishi. It was a surprise for his wife, Fumiko, that Eishi left behind.
Fumiko accepts her late husband's wishes and decides to go to college, and enjoys her days of "learning," which was her dream when she was young. Meanwhile, Takuma, who attends the same university as his grandmother, is worried about his future, not being confident in his own dreams. One day, the two find a mysterious mathematical formula in Eishi's notebook, who loved Mount Fuji. The formula becomes the catalyst for the two to take a step forward.
(source : mydramalist)