American Institute of Mathematics Open Textbook Initiative

Animated Intro to Trig

Calculus

Crash Course: Real College Math (video series)

Crash Course: Statistics

GeoGebra

LibreTexts Mathematics

LibreTexts Statitstics

MIT Open Courseware in Math

Number Theory Free Textbook

OTL Offerings for Calculus

OTL Offerings for Statistics

PHET Interactive Simulations

PreTextBooks Catalog

Statistics

Worfram Math World