Probability Playground
Compare experimental results with theoretical probability and discover the law of large numbers: more trials bring the results closer to the prediction.
Before you try
What if you flipped a coin 1,000 times? Would you get exactly 500 heads?
Try it out
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What happened?
Move a control to see what changes and why.
The coins, dice and spinners here are perfectly fair. Real ones are slightly uneven, and a computer’s random numbers only imitate chance.
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Try these ideas
- Roll one die 10 times, then 1,000 times. Compare the bars.
- Roll two dice. Which total appears most often, and why?
- Change the spinner to 3 sections and predict before you spin.
Why it works
Probability measures how likely something is, from 0 (impossible) to 1 (certain). A fair coin has a 1/2 chance of heads; a fair die has a 1/6 chance of each number; a spinner with 5 equal parts gives 1/5 each.
Run 1, 10, 100 or 1,000 trials and the bars show what actually happened next to the theoretical line. With few trials the results look lumpy; with many, they settle close to the prediction.
Check your understanding
Question 1 of 3
What is the probability of rolling a 4 on a fair six-sided die?
You flip a fair coin 10 times and get 7 heads. What does this tell you?
With two dice, which total is most likely?
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Flip a real coin 20 times together and compare with the simulator.
- Ask: why do casinos and insurance companies rely on large numbers?
- Is a weather forecast of “70% rain” a promise? Discuss.