013 : 1
Start with a problem
Choose a worked example from ratios, fractions, or algebra.
Interactive STEM lessons
See the math.
Understand it.
Free interactive visual lessons for grades 4–6 — ratios, fractions, percentages, averages, age problems and the word problems kids actually get stuck on. Explore each concept one clear step at a time.
23 lessons free to try — no account, no credit card needed.
Live lesson · Ratios
Transfer the oil
Setup: Ratio 3 : 1
Tank A has 3 equal parts, Tank B has 1 equal parts.
A clearer view of
From a word problem to a visual proof
Follow the quantities, see what changes, and test a new value without losing the reasoning.
02A → B
Follow each step
Watch quantities split, combine, and move while the total stays clear.
032 : 1
Try your own values
Change the numbers and see the diagram respond in real time.
Your turn to explore.
Three ways to see a relationship change. Move a control and the engine redraws the model.
Interactive library
Choose a model. Change a value.
A lesson is something you do
Every visual has a job: make the quantities easier to compare, then let you investigate.
An interactive canvas
Crisp SVG diagrams respond to your input. Not a video of someone else doing the math.
Reasoning, step by step
See what changed at each step and move back when you want to look again.
Practice by changing values
Adjust a quantity and watch the model keep up, so patterns become easier to spot.
What you'll master
Build confidence across visual algebra, fractions, and problem-solving strategies, with new areas on the way.
23 free interactive lessons across 5 learning areas — every one shareable with a single link
Line Diagrams
Visual algebra with tape models
Fractions
Parts, wholes, and percentages
Word Problems
Strategies that turn words into diagrams
Visual Geometry
Shapes, angles, and spatial reasoning
Motion & Speed
Distance, time, and rate problems
Free lessons, ready to share
Every lesson opens right in the browser — no account needed. Send one to a parent, a teacher, or your class group chat.
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Transfer Ratio
Watch a ratio change as oil moves between two containers.
Try it free
Average
Pour three uneven tanks level to find the fair share.
Try it free
Age Problems
The age gap never changes — not even years later.
Try it free
Percentage of a Number
A 100-grid makes 25% of 200 impossible to miss.
Try it free
Adding Fractions
Why 1/2 + 1/3 is not 2/5 — shown, not told.
Try it free
Multiplying Fractions
In the area model, the overlap IS the answer.
Try it free
Boat & River Current
Why the same boat makes 24 km/h one way and 16 km/h back.
Try it free
Sum & Difference
Two unknowns, one bar model, zero guessing.
Try it freePlus sum & ratio, difference & ratio, working backwards, the assumption method, interval problems, visual fractions and a pursuit problem — 23 lessons in all, each one a link you can share.
Beyond math — coming soon
stemezy is growing into a full STEM learning platform. Here's what's next on the roadmap.
Coming soon
Physics
Forces, motion, and energy — animated so you can see Newton’s laws in action.
In development
Coming soon
Chemistry
Molecular structures, reactions, and balancing equations — step by visual step.
In development
Coming soon
Programming
Algorithms and data structures explained with animated diagrams, not just code.
In development
Coming soon
More Math
Algebra, geometry proofs, and probability — the library keeps growing.
In development
Want to know when a subject launches? Create a free account and we'll notify you.
Free means free
Every lesson is free — no paywall, and no ads aimed at children.
Free
For every learner.
All 23 lessons free, for everyone
- Every interactive lesson, free to open and share
- Step-by-step playback, live sandbox and practice sets
- New lessons free as they launch
Coming later
Extras for parents and teachers.
Progress tools in development
- Parent progress reports and skill insights
- Printable worksheets for every lesson
- Teacher assignments and class tracking
Lessons stay free, always. If paid extras ever launch, they will be tools for grown-ups — never a paywall on lessons.
Frequently asked questions
Everything parents and students usually ask before starting with stemezy.
stemezy focuses on grades 4 to 6 (about ages 9 to 12) — the years when fractions, ratios and word problems decide whether a child keeps up with math.
No. Every lesson runs smoothly right in a web browser on computers and iPads — just open the link and start learning.
We follow strict child-safety standards, do not collect children’s personal data, and always put student privacy first.
Yes. Each lesson moves one small visual step at a time, helping children understand ideas deeply instead of memorizing formulas.
Yes. Parents can see completed lessons, earned stars, and daily learning streaks directly on the dashboard.
Yes. Every lesson can be opened and shared right in the browser — no account and no credit card needed.
Ready to make math click?
Start exploring with free lessons. No credit card required.