Probability Question Generator
Builds a sheet of probability questions from counters in a bag, at the level you ask for. Every answer is a fraction in its lowest terms, and every one is checked to lie between 0 and 1. Every question is computed and checked directly — not a fabricated or AI-guessed fact.
What this generator does
Generates probability questions with answers — single events, combined events and complements. Answers are given as fractions in their lowest terms, which is the form these questions are usually marked in.
How to use this tool
- Choose a level and how many questions you want.
- Press make questions and work through the sheet.
- Show the answers to mark it, or show the working to see how the favourable outcomes were counted.
- Enter a seed word to rebuild the same sheet later.
Common use cases
- Probability practice at home or school
- Quick maths warm-ups
- Self-testing before a maths quiz
Randomness and fairness
The scenario and its numbers are drawn with the browser's cryptographic random number generator. The probability in each answer is computed exactly rather than estimated, so a question about drawing from a bag reports the true fraction rather than a simulated frequency. A seed word rebuilds the same sheet later; it is for reproducibility, not cryptographic strength, so a seeded sheet is deterministic rather than unpredictable.
For how randomness is produced across the whole site, see how Generate Random works.
Common mistakes
- Adding probabilities that should be multiplied
- Independent events happening together multiply. Mutually exclusive alternatives add. Deciding which situation you have is the whole question.
- Forgetting that removing an item changes the next probability
- Drawing without replacement changes both the numerator and the denominator for the second draw.
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