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

Base Blocks – Illustrate addition and subtraction in a variety of bases. 

Base Blocks Addition – Use base ten blocks to model grouping in addition. 

Base Blocks Decimals – Add and subtract decimal values using base blocks. 

Base Blocks Subtraction – Use base ten blocks to model separation of groups in subtraction. 

Chip Abacus – Learn about carrying and digits using chips. 

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. 

Color Chips  Subtraction – Use color chips to illustrate subtraction of integers. 

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

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

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

Factor Tree – Factor numbers using a tree diagram. 

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

Fraction Pieces – Work with parts and wholes to learn about fractions. 

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

Fractions  Comparing – Judge the size of fractions and plot them on a number line. 

Fractions  Equivalent – Illustrates relationships between equivalent fractions. 

Fractions  Rectangle Multiplication – Visualize and practice multiplying fractions using an area representation. 

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. 

Money – Learn about money by counting and making change. 

Number Line Bars  Fractions – Divide fractions using number line bars. 

Number Line Bounce – Number line addition and subtraction game. 

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. 

Percent Grids – Represent, name, and explore percentages using hundreds grids. 

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

Sieve of Eratosthenes – Relate number patterns with visual patterns. 

Spinners – Work with spinners to learn about numbers and probabilities. 

Tangrams – Use all seven Chinese puzzle pieces to make shapes and solve problems. 

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. 