Pre-K → Grade 10 · free
Algebra, from the very first step
Any child can learn algebra if it starts at the right rung. We break it all the way down — to a toy under a cup — and build it back up, one small idea at a time, to quadratics.
The whole of algebra in one sentence
Something is hiding — and we can work out what it is.
Every grade just makes the hiding spot a little cleverer.
How the hiding number grows up
Twelve grades, four lessons each. Look at the yellow box — that is what the unknown looks like at that age.
- ❓
🧸 Pre-Kindergarten · Ages 3–4
The Hiding Game
One plate has 🍪🍪. The other has 🍪🍪. Is that fair?
- 🎁
🎨 Kindergarten · Ages 5–6
Make It Fair
🎁 and 2 is the same as 5. How many in the box?
- □
🚀 1st Grade · Ages 6–7
The Same As
3 + □ = 7
- ?
🌟 2nd Grade · Ages 7–8
Number Machines
2 → 7, 5 → 10, 8 → 13. What is the rule?
- n
🦋 3rd Grade · Ages 8–9
Letters Are Boxes
4 × n = 20
- n
🌍 4th Grade · Ages 9–10
Number Recipes
Find 3 × n + 2 when n = 6.
- x
🔬 5th Grade · Ages 10–11
Undo It
6x = 42
- x
⚡ 6th Grade · Ages 11–12
Balance and Tip
x ÷ 4 = 3
- x
🧭 7th Grade · Ages 12–13
Two Steps Back
x + 7 = 3
- y = mx + b
🛰️ 8th Grade · Ages 13–14
Lines and Slope
Find the slope of the line through (1, 3) and (3, 7).
- x
🧬 9th Grade · Ages 14–15
Algebra 1
Simplify x² · x³.
- f(x)
🏛️ 10th Grade · Ages 15–16
Curves and Functions
x² − 5x + 6 = 0
🧭 Where should my child start?
Ignore the grade they are in. Find the hardest line they can do comfortably, and tap it.
- Not counting objects yetPre-Kindergarten →
- Counts objects to 10Kindergarten →
- Adds and subtracts within 101st Grade →
- Solves 3 + □ = 72nd Grade →
- Runs a number machine backwards3rd Grade →
- Solves 4 × n = 204th Grade →
- Works out 3 × n + 2 when n = 65th Grade →
- Solves x + 9 = 23 by undoing6th Grade →
- Simplifies 3x + 4 + x and expands 3(x + 2)7th Grade →
- Solves 3x + 4 = 19, including negative answers8th Grade →
- Finds slope and writes y = mx + b9th Grade →
- Factors x² + 7x + 1210th Grade →
⚖️ Solve an equation without writing anything
Get the box on its own using only fair moves. Then press the wrong button and watch the scale tip — that is the one rule of algebra.
Puzzle: 2🎁 + 3 = 11
2🎁 + 3 = 11
Tip: clear the loose dots first, then share. Undo the adding before the multiplying.
Only three moves, ever
Algebra looks like a hundred rules. It is three moves, used on bigger and bigger things.
Keep it balanced
Whatever you do to one side, do to the other. A five-year-old taking a dot off each side of a scale and a sixteen-year-old subtracting 2x from both sides are doing the same thing.
Undo in reverse
To find what went into a machine, run it backwards with the opposite operation. Socks then shoes going on; shoes then socks coming off.
Rewrite it
Say the same thing in a friendlier shape: 3x + 4 + x is 4x + 4, and x² + 7x + 12 is (x + 3)(x + 4). Nothing changes value — it just gets easier to work with.
Frequently Asked Questions
What is algebra, in the simplest words?
Algebra is finding a number that is hiding. You use what you can see — the other numbers and the = sign — to work out what the hidden one must be. The hiding spot starts as a cup over a toy, becomes a box, then a letter like x. Everything else in algebra is a cleverer hiding spot.
What age should a child start algebra?
Three — just not with letters. Patterns and “what’s hiding under the cup?” are algebraic thinking, and the Pre-K page is built from nothing else. Letters arrive in Grade 3, when a child already knows that □ + 6 = 10 has an answer; by then n + 6 = 10 is just a box with a name on it.
My child is in Grade 7 but struggling. Which page should they use?
Use the placement list on this page, not their grade. Find the hardest thing they can do comfortably, and start on the page it points to. Most algebra trouble is a missing rung lower down — very often the Grade 1 idea that = means “is the same as”, not “write the answer here”.
Why is there a balance scale?
Because it is the one picture that works at every age. An equation is a level scale, and solving it means keeping it level while you get the unknown alone. Children press the moves themselves, and there is a deliberately wrong button that tips the scale — seeing it tip teaches the rule faster than hearing it.
Is it free?
Yes. All 48 lessons across twelve grades, every picture and worked example, the balance scale and the practice questions are free with no signup. Practice questions are generated fresh each time, so they never run out, and every one is checked.
Does the Pre-K page need reading?
No. The lessons are written for the adult to say out loud. The practice is pictures and dots the child taps — no reading, writing or typing anywhere.