Free interactive math activities your class can see and change

Round to friendly numbers, break numbers apart, and add left to right, then a practice round with a streak counter where a close estimate counts.

Quick estimation techniques that make everyday calculations a breeze.

Place value in base 2: each position worth double the last. A good stretch after base 10 place value, with conversions both ways and a look at hexadecimal.

How computers think in 1s and 0s - and how you can too.

Students add iterations to a Koch snowflake and see the perimeter grow without limit while the area stays finite, then change the angle and length ratio of a fractal tree.

Build Koch snowflakes, Sierpinski triangles, and fractal trees with adjustable parameters. Watch simple rules create infinite complexity.

Divide consecutive Fibonacci numbers and watch the ratios close in on 1.618, then build the golden spiral from nested rectangles.

The divine proportion hidden in nature, art, and design.

Four rules on a grid, and the Game of Life. Students predict the next generation by hand before pressing play.

Explore Conway's Game of Life and discover how four simple rules create gliders, oscillators, and infinite complexity from a grid of cells.

Click anywhere to read its two numbers, then hunt for given coordinates. A quick warm-up on ordered pairs, negatives, and why screen y grows downward.

Click anywhere to see its two numbers, hunt down coordinates you are given, and find out why screen y grows downward when math class says it grows up.

The Cartesian plane next to screen coordinates, then 3D, polar and texture coordinates: one idea, several systems, and why each one exists.

From Cartesian to polar - understand the grids that power every game and app.

Sliders on y = mx + b, a parabola and a sine wave. Students predict what a change in each number does to the curve, then move it and check.

Explore linear, quadratic, and trigonometric functions through interactive graphing. Adjust slope, curvature, amplitude, and frequency in real time.

Two runners drop a dot every frame, so the spacing is the speed. Students then find the one speed that arrives in exactly a given time: distance, rate and time.

Race two runners that drop a dot every frame, and watch the spacing tell you the speed. Then find the one number that gets you anywhere in exactly the time you want.

A falling ball beside its own frame-by-frame table, where the speed column grows by the same amount every row. A clear look at linear versus nonlinear change.

Drop a ball next to its own frame-by-frame table and watch one column count up by the same amount every single row. That column is gravity.

Measure jumps of different strengths, add up the rise by pairing the first and last steps, and work backward from a target height to the jump strength with a square root.

Step through a jump one frame at a time, measure jumps of different strengths, and find the rule that lets you pick a jump on purpose. The same two lines run every platformer ever made.

Vectors as arrows: add them tip to tail, scale and normalize them, and use the dot product, then launch at a target. A visual first pass before physics or precalculus.

Direction and magnitude - the arrows that power movement in games.

Place two points, find the hidden right triangle between them, and see a squared plus b squared become the distance formula, then extend it to 3D.

The ancient formula that calculates distance in every video game.

Degrees and radians side by side, atan2 turning a point into an angle, and sine and cosine turning an angle back into a point on a circle.

Degrees, radians, and atan2 - the math that makes things turn and aim.

Folding as construction: a fold makes an exact angle bisector, then Maekawa's and Kawasaki's theorems on which crease patterns fold flat.

Discover the mathematical principles hidden in every fold.

Rotational symmetry on a spinning disc, and why a point near the edge moves faster than one near the center at the same angular speed.

Drop paint on a spinning disc with centrifugal physics, explore rotational symmetry, and watch particles fling outward at different speeds.

A kaleidoscope drawing app with 2 to 16 folds. Students draw one stroke at different fold counts and describe the rotational and reflective symmetry they get.

Free, no account. Add a line to a glowing mandala, change the number of folds, and see what one stroke becomes.

Drag sliders on a bracket whose holes stay centered and sized as a share of the spacing: variables and constraints that keep a shape valid.

Explore how parameters drive geometry, see constraints in action on a bracket design, and watch math create spirals, waves, Voronoi cells, and Lissajous curves.

Flip 10, then 1,000 coins and watch the share of heads settle near half, then roll two dice and compare the totals with the 36 possible outcomes.

Flip coins and watch the law of large numbers in action. Roll dice and see why 7 is the most common sum. Explore the Birthday Paradox.

Seeds, weighted chances and loot tables from games. Students finish by building a loot table of their own and setting its odds.

Loot tables, critical hits, and pity systems - the math behind game luck.

Click to add values on a number line and watch the mean and median move apart when one outlier arrives. Ends with histogram shapes: symmetric, skewed, bimodal.

Place data on a number line to see mean vs median diverge, drag an outlier slider to watch averages distort, and explore 4 distribution shapes.

Scatter plots, a trend line that refits as points are added, and correlation versus causation. Students see how far one outlier pulls the line.

Build scatter plots interactively, explore spurious correlations, and toggle outliers to see how one point changes the whole trend.

Sample size and selection bias, and the 1936 election poll that got it wrong. A good opener before students design their own survey.

Polls and surveys try to learn about a big group by asking a small one. Explore how sample size affects accuracy, how selection bias secretly distorts results, and the famous 1936 election poll that got it spectacularly wrong.

Which chart fits which data, and how a truncated axis or a cherry-picked range makes a small change look large.

Learn when to use bar charts, line charts, pie charts, and scatter plots. Spot misleading charts and test your skills with quizzes.

Place points on a map and watch clusters form, read how John Snow found the Broad Street pump, and compare Mercator with an equal-area projection.

Place data points on a world map, explore map projections with Tissot indicatrices, toggle geographic layers, and discover how GIS powers real decisions.