High school math subjects can be challenging for students. Occasionally, a student may need a little extra help or a different explanation in order to clarify a concept or to work a problem. The following websites are a compilation of helpful sites for high school level mathematics including algebra, geometry, trigonometry and calculus.

**Algebra**

Algebasics has the motto of “show me how.” Topics range from basic algebra through quadratics and algebraic applications. Each category has several audio clips along with a visual demonstration of the problem or concept being explained.

Coolmath Algebra has areas for students and teachers. In addition, there is an area to practice different algebra problems. Once the problem is worked, the answer can be checked. The lessons are colorful, bright and easy to follow.

Purplemath has topical listings for problem types from pre-algebra through advanced algebra and beginning trigonometry. The lessons are straightforward lectures with clear explanations and diagrams.

**Trigonometry**

Analyze Math uses Java applets to provide interactive tutorials, problems, formulas and graphs to explore the concepts of trigonometry.

Math World Trigonometry is arranged a bit differently than the other sites. The introductory page presents the primary equations and formulas used in trigonometry. Links are provided throughout the page to explore the topics or ideas in more depth via classroom studies and articles.

Trigonometry Basics Tutorial is a short but interactive introduction to trigonometry concepts. The focus is on helping students visualize and understand the basic concepts of trigonometry.

**Geometry**

Geometry at Thinkquest has lecture style lessons and sample problems for geometry. They have a special page just on constructions.

What I like about Geometry at Math.com are the short explanations with animated diagrams and visual aids. The presentations start with a first glance explanation. This is followed by a more in depth explanation, examples and work out problems.

**Calculus**

On Calculus on the Web or COW, users choose a book from the main categories, which include three levels of calculus, pre-calculus, linear algebra, number theory and abstract algebra. From there modules present problems to be solved. If needed, a help section explains how to solve the problem.

Visual Calculus offers tutorials on Pre-Calculus, limits and continuity, derivatives, differential applications, integration and sequences and series. The tutorials contain step-by-step flash animations, drills, visual notebooks, computer programs and written explanations.

Calculus.org has an extensive list of resources for calculus including links to sample exams, tutorials, animated demonstrations, sample problems and online calculus texts.

**Math Videos**

Khan Academy is one of the best sites for math videos. The videos are short but clearly explain and demonstrate mathematical concepts beginning with elementary math. The site is easy to navigate and contains over 1800 videos arranged topically.

**References**

Free Trigonometry Tutorials and Problems, Analyze Math

Math World Trigonometry, Wolfram Math World

Trigonometry Basics Tutorial, Catcode

Math Videos, Khan Academy

Algebasics, Algebasics

Coolmath Algebra, Coolmath.com

Purplemath, Purplemath

Geometry, Thinkquest

Geometry, Math.com

The Cow Library, Calculus on the Web

Calculus Tutorials, Visual Calculus

The Calculus Page, Calculus.org