Curriculum
Kindergarten
Ages 5–6 · Counting to 100, simple addition & subtraction, shapes and solids.
Counting
Under Numbers
- Skip counting
2, 4, 6, 8 — pick a step and watch a marker hop along.
- Counting
1, 2, 3 — tap to count, hear the rhythm, watch the blocks stack up.
- Colorable number chart
1 to 100 in a 10×10 grid. Click cells to colour them and spot patterns.
- Numerals & digits
What's the difference between a number, a numeral, and a digit?
- Compose & decompose
Break 47 into 4 tens + 7 ones — and put it back together.
- Place value
Why 305 isn't the same as 350 — see digits move between columns.
- Number line
Drag a marker and see negatives, fractions and decimals come alive.
- Cardinal, ordinal & nominal
Three (3), third (3rd), bus #3 — same digits, different jobs.
- Roman numerals
I, V, X, L, C, D, M — type a year and watch it become a Roman numeral.
Addition
Under Numbers
Subtraction
Under Numbers
Measurement
Under Measurement
- Introduction to measurement
What you can measure: length, mass, capacity, time, temperature.
- What is a unit?
A standard chunk you compare other things against — and why standards matter.
- Unit converter
Convert any length, mass, volume, area, speed, or temperature — with the cancel-the-units trick.
- US customary units
Inch, foot, pound, gallon, acre, Fahrenheit — the system that runs the US, with a visual size chart.
- Metric prefixes
kilo, mega, giga, milli, micro, nano — 14 prefixes that scale every metric unit.
- Length
mm, cm, m, km — and inches and feet.
- Metric length
mm, cm, m, km — base 10, easy to convert.
- US customary length
Inch, foot, yard, mile — and the conversions you really need.
- Time
Read clocks, count minutes, work with durations.
- Days, weeks, months, years
How many days in this month? When does the leap year fall?
- Months
Twelve months, names and origins — and how many days each one has.
- Weeks
Seven days, where the names come from, and how the modern week was set.
- Days
Sunrise to sunrise — and the 24 hours in between.
- Years
One trip around the sun — and why it's not exactly 365 days.
- Seasons
Spring, summer, autumn, winter — and the tilt of the Earth that drives them.
- Time units convert
Seconds, minutes, hours, days — convert between any two.
- Stopwatches & timers
Measuring elapsed time — for races, recipes and physics experiments.
- Analog & digital clocks
Two ways to display the same time — read either at a glance.
Showing 18 of 46 — more on the Measurement page.
Time
Under Measurement
- Days, weeks, months, years
How many days in this month? When does the leap year fall?
- Calendar — leap years
Why every fourth year — except some — gets an extra day.
- Time
Read clocks, count minutes, work with durations.
- Months
Twelve months, names and origins — and how many days each one has.
- Weeks
Seven days, where the names come from, and how the modern week was set.
- Days
Sunrise to sunrise — and the 24 hours in between.
- Years
One trip around the sun — and why it's not exactly 365 days.
- Seasons
Spring, summer, autumn, winter — and the tilt of the Earth that drives them.
- Time units convert
Seconds, minutes, hours, days — convert between any two.
- Stopwatches & timers
Measuring elapsed time — for races, recipes and physics experiments.
- Analog & digital clocks
Two ways to display the same time — read either at a glance.
Geometry (Plane)
Under Geometry
- Similar triangles
Same shape, different size — corresponding sides scale together.
- Congruent triangles
Same shape AND same size — SSS, SAS, ASA, AAS, RHS prove it.
- Triangles
The three angles always sum to 180°. Drag to convince yourself.
- Triangle centers
Centroid, circumcenter, incenter, orthocenter — four points every triangle hides.
- Area & perimeter
Resize a rectangle and see area and perimeter follow.
- Interior angles of polygons
Triangle 180°, quad 360°, pentagon 540° — sum grows by 180° per side.
- Exterior angles of polygons
Walk around a polygon — the turns always add to 360°.
- Triangle inequality
Two sides always add to more than the third — or no triangle.
- Right-angle triangle
One 90° corner — and the home of Pythagoras and trig.
- Equilateral triangle
Three equal sides, three 60° angles — the most symmetric triangle.
- Isosceles triangle
Two equal sides — and the base angles are equal too.
- Scalene triangle
All sides different — no symmetry.
- 3-4-5 triangle
The simplest right triangle in whole numbers — used since ancient Egypt.
- Rectangle
Four right angles, opposite sides equal — the most familiar shape.
- Construct triangles
Three sides, two sides and an angle — build a triangle from any combination.
- Rotational symmetry
Spin a shape — does it look the same before a full turn?
- Shapes
Circle, triangle, square, polygon — names, sides, properties.
- Polygons
Three sides, four, five, six… and the angle each interior corner gets.
Showing 18 of 52 — more on the Geometry page.
Geometry (Solid)
Under Geometry
- 3D shapes & volume
Cubes, spheres, cylinders — drag a dimension and watch volume grow.
- Sphere volume & surface
(4/3)πr³ and 4πr² — Archimedes worked these out without calculus.
- Hypercubes
What's a cube in 4 dimensions? Or 5? You can almost picture it.
- Solid geometry
Polyhedra, prisms, pyramids, Platonic solids — Euler's V−E+F = 2.
- Cube
Six squares, twelve edges, eight corners — the simplest 3D solid.
- Sphere
Every point the same distance from the center — the most efficient surface.
- Cylinder
Two circles joined by a tube. Cans, pipes, drums.
- Cone
A circle pulled to a point. Ice-cream, party hats, traffic markers.
- Torus
A donut. One hole, but a surprising amount of geometry.
- Prisms
Same shape, top and bottom — connected by rectangles.
- Pyramids
A polygon base, all sides meeting at one peak.
- Platonic solids
There are exactly five — tetrahedron, cube, octahedron, dodecahedron, icosahedron.
- Nets
Unfold a solid into a flat net — a paper template you can cut and rebuild.
- Tetrahedron
Four triangular faces — the simplest 3D solid.
- Octahedron
Eight triangular faces — like two pyramids glued base to base.
- Dodecahedron
Twelve pentagonal faces — one of the five Platonic solids.
- Icosahedron
Twenty triangular faces — the most spherical of the Platonic solids.
Pre-Algebra
Under Algebra
Data
Under Data
- Pie charts
Slices of a circle — each one a percentage of the whole.
- Charts
Bar, pie, line — the same numbers told three ways.
- Bar graphs
Compare categories at a glance — taller bar means bigger.
- Line graphs
Connect points to track change over time.
- Pictographs
Pictures stand in for counts — friendly charts for small data.
- Histograms
Bar charts for grouped numerical data — bins on the x-axis.
- Dot plots
One dot per data point — see exactly where each value lands.
- Tally marks
The fastest way to count by hand — strokes in groups of five.
- Frequency distribution
How often each value (or range) appears — turn a list into a table.
- Cumulative frequency
Running total — and the curve it builds.
- Scatter plots
Two variables, one dot per data point — patterns appear.
- Stem & leaf plots
An old-school way to see distribution without losing the actual numbers.
- Surveys
Design good questions, gather honest answers, analyse the results.
- Averages
Mean, median, mode, range — interactive.
- Mean
Add them all, divide by how many — the everyday average.
- Weighted mean
Some data points count more — multiply, then divide by total weight.
- Mean deviation
On average, how far is each value from the mean?
- Median
The middle value when sorted — robust against outliers.
Showing 18 of 52 — more on the Data page.
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