Discrete Mathematics: An Open Introduction

Gilbert Strang's complete calculus textbook from MIT OpenCourseWare. Covers differential and integral calculus with an intuitive, application-driven approach.

Gilbert Strang

OpenStax peer-reviewed precalculus textbook (2nd edition) from Rice University. Covers functions, polynomials, trigonometry, vectors, probability, and limits under CC BY 4.0 license.

Jay Abramson, Valeree Falduto, Rachael Gross

Sheldon Axler's landmark textbook on linear algebra (4th edition, Springer Open). Adopted at 375+ universities worldwide, focusing on vector spaces and linear maps over determinants.

Sheldon Axler

OpenStax peer-reviewed statistics textbook from Rice University. Covers descriptive statistics, probability distributions, hypothesis testing, regression, and ANOVA under CC BY 4.0.

Barbara Illowsky, Susan Dean

Classic probability textbook published by the American Mathematical Society. Covers discrete and continuous distributions, combinatorics, central limit theorem, Markov chains, and random walks.

Charles M. Grinstead, J. Laurie Snell