ChanceForge

Roll the dice on real probability. Run experiments, watch the patterns appear, and learn why more data means clearer answers — then practice with the crew who each teach one piece of statistics.

Level 1

For grown-ups — progress report →A private, on-device snapshot mapped to the skill areas practiced. Export a CSV or print — nothing leaves this device.

Probability Lab

Run your own experiments — the same simulations as the iOS app, rebuilt for the browser.

Open the lab Flip coins, roll dice, and watch the law of large numbers settle the odds toward what theory predicts.

Explore the sample space

Two hands-on tools that make the counting behind probability visible.

Sample-Space Grid Shade every outcome of two dice for an event, count them, and watch experiments close in on the theory. Probability-Tree Builder Build a two-stage tree branch by branch and learn why you multiply along a path — not add. 🔍 Detective's Dilemma A good detector still gives lots of false alarms when the thing it looks for is rare. Predict how many flags are real, then read the natural-frequency grid — base-rate reasoning made visible. ⚖️ Fair Sample? Predict which way of choosing who to ask gives the fairest result, then see how a convenience sample skews away from the truth — why how you sample decides whether the answer is trustworthy. 📊 Read the Box Plot A box plot squeezes a whole dataset into five points. Read the median, the middle half, and the range straight off the plot — the picture statisticians use to compare data at a glance.

Practice the concepts

16 kits from collecting data up to statistical inference — a short round of questions with a hint whenever you get stuck. Your progress stays on this device.

Kit 1: Data Collection & Organization Data & Displays · grades 4-5 · 25 questions Kit 2: Graphs & Data Displays Data & Displays · grades 4-5 · 25 questions Kit 3: Mean, Median, Mode & Range Statistics · grades 5-6 · 25 questions Kit 4: Probability Basics Probability · grades 5-6 · 25 questions Kit 5: Experimental vs. Theoretical Probability Probability · grades 5-6 · 25 questions Kit 6: Compound Events & Sample Spaces Probability · grades 6-7 · 25 questions Kit 7: Statistical Variability & Distributions Statistics · grades 6-7 · 25 questions Kit 8: Statistical Inference & Prediction Inference · grades 7-8 · 25 questions Kit 9: Experimental Probability Probability · grades · 25 questions Kit 10: Compound Events & Trees Probability · grades · 25 questions Kit 11: Statistical Distributions Statistics · grades · 25 questions Kit 12: Data-Driven Decision Making Inference · grades · 25 questions Kit 13: Cross-Topic Connections Data & Displays · grades 5-6 · 25 questions Kit 14: Real-World Applications Data & Displays · grades 6-7 · 25 questions Kit 15: Misconceptions & Reasoning Data & Displays · grades 6-7 · 25 questions Kit 16: Advanced Synthesis Data & Displays · grades 7-8 · 25 questions

Play together · new on the web

Chance Duel — a head-to-head kit round for 2–4 players. Take turns on one device, or join a friend in an online room by code. Highest first-try score wins; no chat, no accounts.

⚔️ Start a Chance Duel →

Same idea, another world

Something you practice here shows up somewhere else too — that's real learning that travels.

The chance of an event is favorable outcomes over the total — that is a fraction, a part compared to the whole.The shared idea: part compared to a whole — a probability is favorable outcomes over all outcomes, the same part-of-a-whole idea as a fractionTry FractionForge →Counting favorable outcomes over the total is exactly how a Punnett square predicts which traits an offspring inherits.The shared idea: probability as favorable-over-total — the favorable-over-total you compute for dice is exactly how a Punnett square predicts offspring ratiosTry GeneForge →Counting all the outcomes to find a chance is the same fundamental counting principle — multiply the choices at each step.The shared idea: counting the outcomes — counting all the equally-likely outcomes for a probability is the same fundamental counting principle you multiply choices withTry DiscreteQuest →

More ways to practice

All also on the tab bar above — kept here as quick links:

🔀 Mixed practice — revisit what you’ve learned A short round that shuffles questions from the kits you’ve played, brought back when they’re ready to review. Great for making it stick.

ChanceForge mascot

Meet the cast — the characters who teach this

Each one stands for an idea you’ll practice. Tap a character to read their illustrated story and hear their audio drama.

Ensemble stories — the cast together

Explore all the stories →

📚 Books for ChanceForge

Read the story, print a workbook, or color the cast — free PDFs to read offline or print at home.

Browse all books →

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