Mathematics
SAT Math
Preparation for the Math section of the digital SAT, from essential skills through algebra, advanced math, data analysis and geometry to test strategy.
- Introductory
- Video lessons
- Free
Courses
Pick a course
Every course is free. Course pages list what each course covers and link to the reference sheets and interactive tools that go with it.
Mathematics
Before calculus
Mathematics
Precalculus
The functions, algebra and trigonometry that calculus builds on, from graphs and polynomials to logarithms, vectors, conics and sequences.
- Introductory
- Video lessons
- Free
Mathematics
Foundations for Calculus
The algebra, graphs, exponentials, logarithms and trigonometry that calculus uses on every page, one skill at a time and with the care calculus needs.
- Introductory
- Video lessons
- Free
Calculus
Mathematics
Calculus
Theory and practice video lessons that run from limits and derivatives through integrals, series, Fourier series and differential equations.
- Introductory
- Video lessons
- Free
Calculus
Integrals From Easy to Advanced
One long visual course in 30 chapters that runs from area and Riemann sums through the main integration techniques to multiple integrals, flux and contour integration.
- Intermediate
- Videos coming soon
- Free
Mathematics
Multivariable and Vector Calculus
Calculus in several variables, from vectors and curves in space to partial derivatives, multiple integrals, the theorems of vector calculus and further differential equations.
- Intermediate
- Video lessons
- Free
Mathematics
Differential Equations
A course in differential equations, from first-order methods and linear equations to Laplace transforms, linear systems, nonlinear dynamics, numerical methods, boundary problems and introductory PDEs.
- Intermediate
- Video lessons
- Free
Linear algebra
Mathematics
Linear Algebra I
A first course in linear algebra, from vectors, matrices and linear systems to vector spaces, determinants, orthogonality, least squares, eigenvalues and the singular value decomposition.
- Introductory
- Video lessons
- Free
Mathematics
Linear Algebra II
A proof-based second course on vector spaces, duality, inner products, spectral theory, the singular value decomposition, Jordan form and numerical linear algebra.
- Advanced
- Video lessons
- Free
Probability and statistics
Probability
Introduction to Probability
A first course in probability, from events, counting and conditional probability to random variables, discrete and continuous distributions, limit theorems, simulation and Markov chains.
- Introductory
- Video lessons
- Free
Statistics
Statistics
An introduction to statistics, from describing data and designing studies to probability, estimation, hypothesis tests, regression, Bayesian statistics and time series.
- Introductory
- Video lessons
- Free
Statistics
Multivariate Statistical Analysis
Mean vectors, covariance matrices and the multivariate normal, and the methods built on them, like principal components and discriminant analysis.
- Advanced
- Video lessons
- Free
Applied mathematics
Machine learning
Machine Learning
An introduction to machine learning, from data preparation, regression and classification to model selection, trees and ensembles, clustering, neural networks and responsible deployment.
- Introductory
- Video lessons
- Free
Quantitative finance
Financial Engineering for Quants
The mathematics of pricing, hedging and risk, from no-arbitrage pricing and stochastic calculus to derivatives, numerical methods, interest rates, credit, portfolios and execution.
- Advanced
- Video lessons
- Free
Recreational mathematics
Recreational mathematics
Math That Surprises You
Famous paradoxes, puzzles, number magic and fractals, each a named surprise followed by the mathematics that explains it.
- Introductory
- Video lessons
- Free
Swedish
Swedish has five levels, from A1 to C1. A1 has started and the other levels are planned. See all Swedish levels
Swedish
Swedish A1
Swedish for complete beginners in nine chapters of short written lessons, with explanations in English and examples in Swedish, from greetings to work, health and weather.
- Introductory
- Level A1
- Written lessons
- Free