
Abacus – An electronic abacus that can be used to do arithmetic. 

Circle 0 – A puzzle involving adding positive and negative integers to sum to zero. 

Circle 21 – A puzzle involving adding positive and negative integers to sum to twenty one. 

Circle 3 – A puzzle involving adding positive real numbers to sum to three. 

Circle 99 – A puzzle involving adding positive and negative integers to sum to ninety nine. 

Conway's Game of Life – Discover the rules that determine change in these simulations. 

Counting All Pairs – Create a path that sets up a onetoone correspondence between the counting numbers and infinite sets of ordered pairs of integers. 

Diffy – Solve an interesting puzzle involving the differences of given numbers. 

Dueling Calculators – Visualize a dramatic simulation of the effect of propagating rounding errors. 

Fibonacci Sequence – Explore the Fibonacci sequence and the golden ratio. 

Fractions  Adding – Illustrates what it means to find a common denominator and combine. 

Fractions  Equivalent – Illustrates relationships between equivalent fractions. 

Function Machine – Explore the concept of functions by putting values into this machine and observing its output. 

Golden Rectangle – Illustrates iterations of the Golden Section. 

Grapher – A tool for graphing and exploring functions. 

Mastermind – Use inference and logic to play a game and guess a hidden pattern of pegs. 

Number Puzzles – Solve puzzles involving arranging numbers on a diagram so that they add up to a given value. 

Pascal's Triangle – Explore patterns created by selecting elements of Pascal's triangle. 

Peg Puzzle – Win this game by moving the pegs on the left past the pegs on the right. 

Percentages – Discover relationships between fractions, percents, and decimals. 

Rational Numbers Triangle – Explore a triangular array that contains every positive rational number exactly once. 

Sieve of Eratosthenes – Relate number patterns with visual patterns. 

Tight Weave – Visualize the creation of the Sierpinski Carpet, an iterative geometric pattern that resembles a woven mat. 

Turtle Geometry – Explore numbers, shapes, and logic by programming a turtle to move. 

Venn Diagrams – Investigate common features of sets. 