Mathematics
59 sites
http://math2.org/
Math2.org is a comprehensive math reference site offering organized tables, formulas, and identities covering everything from basic arithmetic to calculus, linear algebra, and Fourier transforms. Available in both English and Spanish, it also features a message board for math questions and links to other top math resources on the web.
https://nsml.org/
The North Suburban Math League (NSML) organizes competitive math meets for Chicago-area high schools, with five competitions held throughout the school year. The site provides contest archives, meet schedules, written and oral topic lists, coach resources, and a history of NSML alumni who have earned medals at the International Mathematical Olympiad.
https://knotplot.com/
Created by Robert G. Scharein, the KnotPlot Site is a visually stunning exploration of mathematical knot theory, featuring hundreds of images and animations generated by the KnotPlot software for Windows, macOS, and Linux. Visitors can browse galleries of torus knots, Celtic knots, hyperbolic knots, Brunnian links, and fractal structures, as well as download the KnotPlot program itself to visualize and manipulate knots in three and four dimensions.
https://www.mathsisfun.com/links/external.html
A curated collection of external math links from MathIsFun, organized into math websites, fun puzzle sites, and schools, covering everything from algebra and geometry to game theory and Pi. Created by Rod Pierce, this page serves as a springboard to some of the web's best math resources for students, teachers, and curious minds alike.
https://math.ucr.edu/home/baez
John Baez is a mathematical physicist and emeritus professor at UC Riverside whose sprawling personal site features decades of expository writing on math and physics, including his long-running column 'This Week's Finds in Mathematical Physics.' Visitors can explore course notes, research papers, talks on topics from category theory to the Standard Model, and accessible blog posts bridging cutting-edge science with public engagement.
http://eveandersson.com/pi
Pi Land is Eve Andersson's comprehensive tribute to the mathematical constant pi, featuring trivia games, a memory trainer, digit search tools, frequency analysis, and multiple calculation methods including Gregory-Leibniz and Monte Carlo. The site blends nerdy exploration with aesthetic touches like poetry, photos, and art, making it a delightful destination for math enthusiasts of all levels.
http://joyofpi.com/pilinks.html
A comprehensive link directory dedicated entirely to pi, curated by David Blatner, author of 'The Joy of Pi,' covering everything from basic pi facts and digit downloads to pi music, pi history, and Pi Day celebrations. Visitors will find hundreds of categorized links spanning memorizing pi, calculating digits, pi mysteries, and even wacky pi fun, making it a go-to hub for pi enthusiasts of all levels.
https://secure1.ed.brocku.ca/~rahul/Misc/pi.html
A page by a student or researcher at Brock University presenting the first 10,000 decimal digits of pi, calculated using Machin's formula on a Silicon Graphics MIPS R4400 workstation. It offers a concise glimpse into early 1990s academic computing power applied to a classic mathematical challenge.
https://hermetic.ch/cal_stud/jdn.htm
Peter Meyer's detailed reference article explains the Julian Day Number system, covering its origins, astronomical vs. chronological uses, and various related date formats like Modified Julian Day Numbers and Lilian Day Numbers. The page includes conversion algorithms and links to calendar software tools, making it a thorough technical reference for astronomers, historians, and calendricists.
https://complex-analysis.com/
Created by Juan Carlos Ponce Campuzano, this interactive online textbook introduces complex analysis through visual applets built with GeoGebra, p5.js, and other JavaScript tools, making abstract mathematical concepts tangible and explorable. Covering topics from the Cauchy-Goursat Theorem to conformal mappings, it serves engineering and mathematics students with a beautifully designed, continually updated resource that includes Spanish and Italian translations.