Dictionary cut-the-knot.org
Dictionary of Units
E-Books onlinebooks.library.upenn
History of Math Univ. of St. Andrews, Scotland
History of Math David E. Joyce
Units of Measurement Frank Tapson
Metric Conversions beyond.fr
Statistics

Math in the Classroom
Lesson Plans Math Archives
Lesson Plans Math Forum
Lesson Plans atozteacherstuff

EXERCISES & QUIZZES

Geometry Michael Christoffel
Fibonacci Puzzles Ron Knott
Riemann Hypothesis audio / John Derbyshire
Topology Math Forum

Exercises advanced math / grades 5-7 / Don & Jerre McQuinn
Exercises interactive lessons / Math Goodies
Exercises Cynthia Lanius
Exercises Math Mastery / Systems Impact, Inc.
Exercises Brain Teasers / Houghton Mifflin
Quizzes Amby Duncan Carr
Quizzes Family Education
Quizzes Internet School Bus
Quizzes Math for Morons Like Us
Quizzes Pearson Adult Learning Centre
Quizzes Syvum
Quizzes Tela Communications