A free program for Android, by Sangakoo.
This is a free educational resource for studying math.
The app is made by an interdisciplinary team of educators. The goal is to offer a complete and easy-to-use mathematical theory to all students, from those who are just starting to learn mathematics to those who have already taken a course in mathematics. The team has designed a very didactic and easy-to-understand format to help the students better learn and understand the subject.
We have organized the contents of the app into nine essential branches of mathematics: algebra, geometry, calculation and analysis, applied mathematics, probability and statistics, fundamentals, discrete mathematics, and number theory.
Each branch is divided into subjects, based on the level of difficulty of the subject.