Semi wa Magic Cube
Genres: Action, Comedy, Fantasy
Type: ONA, Episodes: 26
Aired: Aug 1, 2018 to Feb 7, 2019
Studio: Durufix
Source: Original
Rating: PG-13 - Teens 13 or older
Synopsis:
The story tells the tale of Semi, a bright girl who goes in a magical time journey with the genius teacher Wai, in order to prevent the evil X from utilizing the powers of the magic cube for evil. Along the way, Semi and her math school friends run into history and math problems that they must solve with logic and wit.

(Source: hobbykr)