Wolfram Research: «The Mathematical Explorer (PC)»

The Mathematical Explorer is recreational software for mathematics hobbyists and others intrigued by mathematics and some of its more challenging topics. Delving into some of the most important mathematical concepts, The Mathematical Explorer combines text, graphics, and formulas in an easy-to-use notebook interface that is completely interactive. Lessons cover a wide range of topics and contain a wealth of relevant information, including historical introductions and biographies where applicable, questions and answers, and related notes and references.