Khan Academy is an educational resource known throughout the world by teachers and students alike. When you’re confused on a topic, Sal Khan will (almost) always explain it better. With such brilliant quality, Khan Academy has branched out, covering subjects such as AP Economics and Psychology and many more, while still maintaining high standards for its K-12 math curriculum.

This one is for the little ones! Set in a fantasy game background, this app allows children from grades 1 - 8 to practice their mathematical skills interactively. While maximizing engagement through games, Prodigy also maximizes learning as teachers can supervise and report back on children’s progress.

LibGen provides free access to a wide range of journal articles, textbooks, and other forms of media that are mostly otherwise behind a paywall. The ability to download free textbooks is especially helpful to students at locations where resource access is lacking. To prevent downloading unwanted viruses, it is best to avoid torrenting; rather, download files directly from the site.

The most popular global video platform, YouTube has long hosted a substantial community of learners and teachers. With nearly all video content is available free of charge, it is a go-to resource for a student’s questions on any topic.

RemNote is a note-taking application, available on mobile, as a web app, and on desktop, that allows users to create spaced-repetition flashcards within a hierarchic text structure. This functionality takes full advantage of the forgetting curve to optimize memory retention for notes that would otherwise exist in plain text. All of the essentials come with the free version of the app.

Paul’s Math Notes is a comprehensive database of math notes and practice problems curated by a professor at Lamar University. Covering Algebra, Trigonometry, Calculus I, II, III, and Differential Equations, these notes contain great detail and expertise and are an amazing source of reference for any math-related confusions.

“For students. By students.” On Brainly, students’ questions are answered by other students, providing leveled and accessible explanations while deepening the understanding of all parties. Furthermore, Brainly serves as a social platform where students can connect via their love for mathematics!

Fiveable is a global community of Advanced Placement students which offers virtual study groups and well-curated study guides and content for every single AP exam administered by the College Board. Also providing help for students with many different aspects of the US college admissions process, its services are completely free of charge.

Crash Course is a long-established online course database that extensively covers a wide range of subjects, from astronomy to philosophy to law, history, and science. Their videos are of very high quality, though it is important to note that their content is not specifically aligned with any major high school curriculum.

Desmos is a powerful online graphing calculator tool that has expanded to offer a variety of other calculators, a middle school math curriculum, classroom activities, and even graphing art competitions. Unlike many physical or other digital graphing calculators, Desmos has an uncluttered and simple user interface and offers its essential services free of charge.

The United Kingdom Mathematics Test is an annual international test designed to stretch students’ problem solving capabilities, not their prior knowledge. Various levels of problem solving questions targeted anywhere from grades 6 to 12 can be found on this website aiming to stretch students and examine their ability to think outside the box.

Coursera’s online courses, largely administered by world-renowned universities and companies, cover all fields of study and allow for many flexible aspects in learning. Its courses vary from simple lecture series to full professional degrees. Though many courses require payment, a large number of high-quality classes are offered free of charge and some paid programs allow for free viewing of content (“auditing”), though without graded assignments.

Edx is a database of courses provided by universities, private companies and even international organizations. From skill-learning such as coding to academic learning such as topology, Edx provides courses for any and all interests. While certification is priced, most courses are available for free.