Welcome to Eric Weisstein's World of mathematics! 9,826 entries, 172,470 cross references and 4,050 figures and counting!
The Abacus ~ The Art of Calculating with Beads
This site presents the most complete information on the history and use of the Abacus that we have ever seen.
Printable Math activities and Math help
A wealth of printable resources on Mathematics, Number Theory, Combinatorics/number counting, Geometry, Algebra, Calculus/Differential Equations, Probability/Statistics.
U of Victoria Computer Science
Professor, Dr. Mike Fellows.
Great for probability experiments!
Math Sketchpad for Little Ones
Contains over 200 single concept lessons. Categories include geometry and measurement, patterns and logic, and practical and applied math.