Free Online Classes & Video Tutorials
A growing number of videos, exercises and lesson plans for self-paced learning.
The majority of video content on this page is provided by Khan Academy, a nonprofit organization with a mission to provide a free, world-class education for anyone, anywhere.
We are deeply grateful to Khan Academy for making these educational resources freely available to learners worldwide. Visit Khan Academy →
Featured Video Lessons
Solving quadratic equations Basic example
Watch Sal work through a basic Solving quadratic equations problem.
Angle Basics
Definition of an angle. How to denote an angle using points on the angle (including the vertex)
Introduction to Evolution and Natural Selection
Introduction to evolution, variation in a population and natural selection
Euclid as the Father of Geometry
Euclid and his Elements (and how much Abraham Lincoln liked them)
Reading: Science — How-to Part 1
Watch Sal work through Part 1 of an SAT Reading: Science passage.
Algebra I
16 videos
Khan Academy: History of the World
16 videos
Algebra: Introduction to Algebra
4 videos
Algebra: Solving Linear Equations
60 videos
Geometry: Angles
35 videos
Geometry: Basic Geometry
8 videos
About the SAT
5 videos
Additional Topics in Math
15 videos
Heart of Algebra
18 videos
Passport to Advanced Math
28 videos
Problem Solving & Data Analysis
20 videos
Reading & Writing
43 videos
Khan Academy: Biology
14 videos