Abacus — An electronic abacus that can be used to do arithmetic. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Algebra Balance Scales — Solve simple linear equations using a balance beam representation. Algebra (6–8), Algebra (9–12)
Algebra Balance Scales  Negatives — Solve simple linear equations using a balance beam representation. Algebra (6–8), Algebra (9–12)
Algebra Tiles — Visualize multiplying and factoring algebraic expressions using tiles. Algebra (PreK–2), Algebra (3–5), Algebra (6–8), Algebra (9–12)
Attribute Blocks — Learn color and shape concepts by sorting blocks. Geometry (PreK–2), Measurement (PreK–2), Geometry (3–5), Measurement (3–5)
Attribute Trains — Learn about shape and color patterns of by completing trains of blocks. Geometry (PreK–2), Measurement (PreK–2), Geometry (3–5), Measurement (3–5), Geometry (6–8), Measurement (6–8)
Bar Chart — Create a bar chart showing quantities or percentages by labeling columns and clicking on values. Number & Operations (PreK–2), Data Analysis & Probability (PreK–2), Number & Operations (3–5), Data Analysis & Probability (3–5), Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Base Blocks — Illustrate addition and subtraction in a variety of bases. Number & Operations (PreK–2), Number & Operations (3–5), Algebra (3–5), Number & Operations (6–8), Algebra (6–8), Algebra (9–12)
Base Blocks Addition — Use base ten blocks to model grouping in addition. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8)
Base Blocks Decimals — Add and subtract decimal values using base blocks. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8)
Base Blocks Subtraction — Use base ten blocks to model separation of groups in subtraction. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8)
Block Patterns — Analyze sequences of figures using pictures, tables, plots, and graphs. Algebra (6–8), Algebra (9–12)
Box Model — Randomly selects and displays draws from a box. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Box Plot — Use this tool to summarize data using a box plot graph. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Chip Abacus — Learn about carrying and digits using chips. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8)
Circle 0 — A puzzle involving adding positive and negative integers to sum to zero. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Circle 21 — A puzzle involving adding positive and negative integers to sum to twenty one. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Circle 3 — A puzzle involving adding positive real numbers to sum to three. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Circle 99 — A puzzle involving adding positive and negative integers to sum to ninety nine. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Cob Web Plot — Change variables and observe patterns from this graphing simulation. Geometry (6–8), Geometry (9–12)
Coin Problem — Use deduction to find the counterfeit coin. Algebra (6–8), Algebra (9–12)
Coin Tossing — Explore probability concepts by simulating repeated coin tosses. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Color Chips  Addition — Use color chips to illustrate addition of integers. Number & Operations (PreK–2), Number & Operations (3–5)
Color Chips  Subtraction — Use color chips to illustrate subtraction of integers. Number & Operations (3–5), Number & Operations (6–8)
Color Patterns — Arrange colors to complete a pattern. Number & Operations (PreK–2), Algebra (PreK–2), Number & Operations (3–5), Algebra (3–5)
Congruent Triangles — Build similar triangles by combining sides and angles. Geometry (PreK–2), Geometry (3–5), Geometry (6–8)
Converting Units — Use a simple system for converting units. Measurement (3–5), Measurement (6–8), Measurement (9–12)
Conway's Game of Life — Discover the rules that determine change in these simulations. Number & Operations (6–8), Number & Operations (9–12)
Counting All Pairs — Create a path that sets up a onetoone correspondence between the counting numbers and infinite sets of ordered pairs of integers. Number & Operations (9–12)
Diffy — Solve an interesting puzzle involving the differences of given numbers. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Dueling Calculators — Visualize a dramatic simulation of the effect of propagating rounding errors. Number & Operations (6–8), Number & Operations (9–12)
Factor Tree — Factor numbers using a tree diagram. Number & Operations (3–5), Number & Operations (6–8), Algebra (6–8)
Fibonacci Sequence — Explore the Fibonacci sequence and the golden ratio. Number & Operations (6–8), Number & Operations (9–12)
Fifteen Puzzle — Solve this virtual version of the classical fifteen puzzle by arranging its tiles. Algebra (PreK–2), Algebra (3–5), Algebra (6–8), Algebra (9–12)
Fill and Pour — Solve puzzles requiring you to fill and pour containers. Measurement (3–5), Measurement (6–8), Measurement (9–12)
Fractals  Iterative — Generate six different fractals. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Fractals  Koch and Sierpinski — Change colors and pause this fractal simulation at any point. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Fractals  Mandelbrot and Julia Sets — Investigate relationships between these two fractal sets. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Fractals  Polygonal — Change the parameters to create a new fractal. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Fraction Bars — Learn about fractions using fraction bars. Number & Operations (PreK–2), Number & Operations (3–5)
Fraction Pieces — Work with parts and wholes to learn about fractions. Number & Operations (3–5), Number & Operations (6–8)
Fractions  Adding — Illustrates what it means to find a common denominator and combine. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Fractions  Comparing — Judge the size of fractions and plot them on a number line. Number & Operations (3–5), Number & Operations (6–8)
Fractions  Equivalent — Illustrates relationships between equivalent fractions. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Fractions  Naming — Write the fraction corresponding to the highlighted portion of a shape. Number & Operations (PreK–2), Number & Operations (3–5)
Fractions  Parts of a Whole — Relates parts of a whole unit to written description and fraction. Number & Operations (PreK–2), Number & Operations (3–5)
Fractions  Rectangle Multiplication — Visualize and practice multiplying fractions using an area representation. Number & Operations (3–5), Number & Operations (6–8)
Fractions  Visualizing — Illustrate a fraction by dividing a shape and highlighting the appropriate parts. Number & Operations (PreK–2), Number & Operations (3–5)
Function Machine — Explore the concept of functions by putting values into this machine and observing its output. Number & Operations (6–8), Algebra (6–8), Number & Operations (9–12), Algebra (9–12)
Function Transformations — Explore how simple transformations affect the graph of a function. Algebra (6–8), Algebra (9–12)
Geoboard — Use geoboards to illustrate area, perimeter, and rational number concepts. Geometry (PreK–2), Measurement (PreK–2), Geometry (3–5), Measurement (3–5), Geometry (6–8), Measurement (6–8), Geometry (9–12), Measurement (9–12)
Geoboard  Circular — Use circular geoboards to illustrate angles and degrees. Geometry (3–5), Measurement (3–5), Geometry (6–8), Measurement (6–8), Geometry (9–12), Measurement (9–12)
Geoboard  Coordinate — Rectangular geoboard with x and y coordinates. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Geoboard  Isometric — Use geoboard to illustrate threedimensional shapes. Geometry (PreK–2), Geometry (3–5), Geometry (6–8), Geometry (9–12)
Golden Rectangle — Illustrates iterations of the Golden Section. Geometry (3–5), Number & Operations (6–8), Geometry (6–8), Number & Operations (9–12), Geometry (9–12)
Grapher — A tool for graphing and exploring functions. Number & Operations (3–5), Algebra (3–5), Number & Operations (6–8), Algebra (6–8), Number & Operations (9–12), Algebra (9–12)
Great Circle — Use a 3D globe to visualize and measure the shortest path between cities. Geometry (6–8), Measurement (6–8), Geometry (9–12), Measurement (9–12)
Hamlet Happens — Verify that rare events happen by drawing letters from a box. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Histogram — Use this tool to summarize data using a histogram graph. Data Analysis & Probability (3–5), Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
How High? — Try your hand at the classic Piagetian conservation of volume test. Geometry (6–8), Measurement (6–8), Measurement (9–12)
Hundreds Chart — Practice counting and visualize number patterns using a hundreds chart. Number & Operations (PreK–2), Number & Operations (3–5)
Ladybug Leaf — Program a ladybug to hide behind a leaf. Geometry (PreK–2), Measurement (PreK–2), Geometry (3–5), Measurement (3–5), Geometry (6–8), Measurement (6–8)
Ladybug Mazes — Program a ladybug to move through a maze. Geometry (PreK–2), Measurement (PreK–2), Geometry (3–5), Measurement (3–5), Geometry (6–8), Measurement (6–8)
Line Plotter — Practice drawing lines through a given point having a specified slope. Algebra (6–8), Algebra (9–12)
Loan Calculator — Explore how to pay off a loan, and how interest affects payment. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Mastermind — Use inference and logic to play a game and guess a hidden pattern of pegs. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Money — Learn about money by counting and making change. Number & Operations (PreK–2), Measurement (PreK–2), Number & Operations (3–5), Measurement (3–5), Number & Operations (6–8), Measurement (6–8)
Number Line Arithmetic — Illustrates arithmetic operations using a number line. Number & Operations (PreK–2), Number & Operations (3–5)
Number Line Bars — Use bars to show addition, subtraction, multiplication, and division on a number line. Number & Operations (PreK–2), Number & Operations (3–5)
Number Line Bars  Fractions — Divide fractions using number line bars. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8)
Number Line Bounce — Number line addition and subtraction game. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8)
Number Patterns — Discover the pattern and complete a sequence of numbers. Number & Operations (PreK–2), Number & Operations (3–5)
Number Puzzles — Solve puzzles involving arranging numbers on a diagram so that they add up to a given value. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Pascal's Triangle — Explore patterns created by selecting elements of Pascal's triangle. Number & Operations (6–8), Number & Operations (9–12), Data Analysis & Probability (9–12)
Pattern Blocks — Use six common geometric shapes to build patterns and solve problems. Algebra (PreK–2), Geometry (PreK–2), Measurement (PreK–2), Algebra (3–5), Geometry (3–5), Measurement (3–5), Algebra (6–8), Geometry (6–8), Measurement (6–8), Algebra (9–12), Geometry (9–12), Measurement (9–12)
Peg Puzzle — Win this game by moving the pegs on the left past the pegs on the right. Number & Operations (3–5), Number & Operations (6–8), Algebra (6–8), Number & Operations (9–12), Algebra (9–12)
Pentominoes — Use the 12 pentomino combinations to solve problems. Algebra (PreK–2), Geometry (PreK–2), Algebra (3–5), Geometry (3–5), Algebra (6–8), Geometry (6–8), Algebra (9–12)
Percent Grids — Represent, name, and explore percentages using hundreds grids. Number & Operations (3–5), Number & Operations (6–8)
Percentages — Discover relationships between fractions, percents, and decimals. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Pie Chart — Explore percentages and fractions using pie charts. Number & Operations (PreK–2), Data Analysis & Probability (PreK–2), Number & Operations (3–5), Data Analysis & Probability (3–5), Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Pinwheel Tiling — Construct and explore a very unusual tiling of the plane by right triangles. Geometry (9–12)
Place Value Number Line — Explore place value by placing dots on number lines. Number & Operations (PreK–2), Number & Operations (3–5)
Platonic Solids — Identify characteristics of the Platonic Solids. Geometry (PreK–2), Geometry (3–5), Geometry (6–8), Geometry (9–12)
Platonic Solids  Duals — Identify the duals of the platonic solids. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Platonic Solids  Slicing — Discover shapes and relationships between slices of the platonic solids. Geometry (6–8), Geometry (9–12)
Point Plotter — Practice plotting ordered pairs on a graph. Algebra (6–8), Algebra (9–12)
Polyominoes — Build and compare characteristics of biominoes, triominoes, quadrominoes, etc. Algebra (PreK–2), Algebra (3–5), Algebra (6–8), Geometry (6–8), Algebra (9–12), Geometry (9–12)
Pythagorean Theorem — Solve two puzzles that illustrate the proof of the Pythagorean Theorem. Geometry (6–8), Geometry (9–12)
Rational Numbers Triangle — Explore a triangular array that contains every positive rational number exactly once. Number & Operations (9–12)
Rectangle Division — Visualize and practice dividing numbers by using an area representation. Number & Operations (PreK–2), Number & Operations (3–5)
Rectangle Multiplication — Visualize the multiplication of two numbers as an area. Number & Operations (PreK–2), Number & Operations (3–5)
Rectangle Multiplication of Integers — Visualize and practice multiplying integers using an area representation. Number & Operations (PreK–2), Number & Operations (3–5)
Right Triangle Solver — Practice using the Pythagorean theorem and the definitions of the trigonometric functions to solve for unknown sides and angles of a right triangle. Geometry (9–12)
Savings Calculator — Explore how savings, with or without regular deposits, grow over time. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Scatterplot — Plot multiple data points in two dimensions and determine correlation. Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Sieve of Eratosthenes — Relate number patterns with visual patterns. Number & Operations (PreK–2), Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Space Blocks — Create and discover patterns using three dimensional blocks. Geometry (PreK–2), Algebra (3–5), Geometry (3–5), Algebra (6–8), Geometry (6–8), Geometry (9–12)
Spinners — Work with spinners to learn about numbers and probabilities. Number & Operations (PreK–2), Data Analysis & Probability (PreK–2), Data Analysis & Probability (3–5), Number & Operations (6–8), Data Analysis & Probability (6–8), Data Analysis & Probability (9–12)
Stick or Switch — Investigate probabilities of sticking with a decision, or switching. Algebra (6–8), Data Analysis & Probability (6–8), Algebra (9–12), Data Analysis & Probability (9–12)
Tangrams — Use all seven Chinese puzzle pieces to make shapes and solve problems. Geometry (PreK–2), Number & Operations (3–5), Geometry (3–5), Measurement (3–5), Number & Operations (6–8), Geometry (6–8), Measurement (6–8), Geometry (9–12)
Tessellations — Using regular and semiregular tessellations to tile the plane. Geometry (PreK–2), Geometry (3–5), Geometry (6–8), Geometry (9–12)
Tight Weave — Visualize the creation of the Sierpinski Carpet, an iterative geometric pattern that resembles a woven mat. Number & Operations (6–8), Geometry (6–8), Number & Operations (9–12), Geometry (9–12)
Time  Analog and Digital Clocks — Interactively set the time on a digital and analog clocks. Measurement (PreK–2), Measurement (3–5)
Time  Match Clocks — Answer questions asking you to show a given time on digital and analog clocks. Measurement (PreK–2), Measurement (3–5)
Time  What Time Will It Be? — Answer questions asking you to indicate what time it will be before or after a given time period. Measurement (PreK–2), Measurement (3–5), Measurement (6–8)
Towers of Hanoi — Solve the tower problem and test your theory by varying the number of disks. Algebra (3–5), Algebra (6–8), Algebra (9–12)
Transformations  Composition — Explore the effect of applying a composition of translation, rotation, and reflection transformations to objects. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Transformations  Dilation — Dynamically interact with and see the result of a dilation transformation. Geometry (3–5), Geometry (6–8), Geometry (9–12)
Transformations  Reflection — Dynamically interact with and see the result of a reflection transformation. Geometry (PreK–2), Geometry (3–5), Geometry (6–8), Geometry (9–12)
Transformations  Rotation — Dynamically interact with and see the result of a rotation transformation. Geometry (PreK–2), Geometry (3–5), Geometry (6–8), Geometry (9–12)
Transformations  Translation — Dynamically interact with and see the result of a translation transformation. Geometry (PreK–2), Geometry (3–5), Geometry (6–8), Geometry (9–12)
Triangle Solver — Practice using the law of sines and the law of cosines to solve for unknown sides and angles of a triangle. Geometry (9–12)
Triominoes — Manipulate the puzzle pieces and find multiple solutions. Algebra (PreK–2), Geometry (PreK–2), Algebra (3–5), Geometry (3–5), Algebra (6–8), Geometry (6–8)
Turtle Geometry — Explore numbers, shapes, and logic by programming a turtle to move. Geometry (PreK–2), Geometry (3–5), Number & Operations (6–8), Geometry (6–8), Number & Operations (9–12), Geometry (9–12)
Turtle Rectangles — Change variables to observe differences in spiral designs. Algebra (PreK–2), Algebra (3–5)
Venn Diagrams — Investigate common features of sets. Number & Operations (3–5), Number & Operations (6–8), Number & Operations (9–12)
Whammy Awards — See how using different voting schemes can result in contradictory outcomes. Data Analysis & Probability (9–12)
