PlanetMath - A collaborative encyclopaedia with entries contributed under the GNU Free Documentation License. K-12 math textbook content analysis - Spreadsheets on the distribution of 1000 common math terms as used in K-12th grade mathematics textbooks over the last 30 years. Analysis in English, Spanish and French. NIST Digital Library of Mathematical Functions - Result of a project to provide a modern revision of Abramowitz and Stegun’s "Handbook of Mathematical Functions". The site includes definitions, properties, and graphs of many special functions. Platonic Realms - Online resource for the mathematics community: links library, bookstore, quotes, and online articles. Summation Formulae - For polynomials of degrees up to 50, generated using the Euler-Maclaurin method. Geometry Formulas and Facts - An excerpt from the 30th Edition of the CRC Standard Mathematical Tables and Formulas, covering the area of Geometry (minus differential geometry), by Silvio Levy. Wolfram: Mathematical Functions - Includes advanced formulas and visualizations of various equations, such as elliptic curves. The Math Reference Project - An electronic archive of articles by Karl Dahlke on topics ranging from high school geometry up to graduate level topology. Equations - Searchable directory, arranged by field, of equations, constants, symbols and SI units. Also features LaTEX utilities, software links. Numerical Prefixes - Tables for Greek and Latin number values alone and as a part of other words. The On-Line Encyclopedia of Integer Sequences (OEIS) - Identify a sequence by entering few terms in the sequence. Additional information includes examples, formulas, and related links. Math Tube - Mathematics lecture videos and talks taken from The Pacific Institute for the Mathematical Sciences (PIMS) member universities and around the world. Tricki - A large collection of useful mathematical problem-solving techniques. Web Formulas - Web Formulas provides collections of formulas used in math, physics and chemistry. Mathematics Notes - Exposition of the basic concepts and theory of various subjects including matrix theory, calculus, modern abstract algebra, linear algebra, plane analytic geometry and solid analytic geometry. Math formulas - A large , free online lists of mathematics formulas. Collection of all basic and advanced formulas related to mathematics. Math Open Reference - An online interactive Math textbook. Wikipedia: Mathematics Portal - Free crowd-sourced encyclopedia. Covers number systems, different math fields, foundations, history, applications, and famous problems. Encyclopedia of Mathematics - Open access encyclopaedia, based on Kluwer edition of 2002.