Introduction to Probability
Class 9 · Mathematics
3 ideas in Class 9 Mathematics, explained in plain words, with games and quizzes to practise.
Probability and Likelihood
Part of: Probability and Likelihood
Probability ranges from 0 for impossible to 1 for certain. Values between them describe degrees of likelihood; one half means equal chance.
Why it matters. Probability helps describe uncertainty using a common scale.
Try it in two minutes
- Check whether an event can happen.
- Compare its chance with an even chance.
- Place it between zero and one.
Try at home. Rank everyday events by how likely they are.
Experimental and Theoretical Probability
Part of: Experimental and Theoretical Probability
Theoretical probability compares favourable outcomes with all equally likely outcomes. Experimental probability uses how often an event occurred in collected trials.
Why it matters. Evidence and outcome counts support probability estimates.
Try it in two minutes
- Count favourable outcomes.
- Count all outcomes or trials.
- Divide the first count by the second.
Try at home. Record results from repeated coin tosses and compare with one half.
Sample Spaces, Events and Trees
Part of: Sample Spaces, Events and Trees
A sample space lists all possible outcomes. An event is a subset of that space. A tree diagram shows the paths and outcomes of a multi-step experiment.
Why it matters. A complete list prevents outcomes from being missed.
Try it in two minutes
- List each possible result of one step.
- For multiple steps, pair each first result with each next result.
- Select outcomes that meet the event condition.
Try at home. Make a tree for two choices followed by two choices.
What your child will practise
- Experimental and Theoretical Probability: Candy Quick Fire (Quick Fire)
- Experimental and Theoretical Probability: Number Quest (Collect the Answer)
- Experimental and Theoretical Probability: Ocean Puzzle (Clue Puzzle)
- Probability and Likelihood: Mission Control Quest (Match It Up)
- Sample Spaces, Events and Trees: Space Quick Fire (Quick Fire)
- Quiz: Experimental and Theoretical Probability (8 questions)
- Quiz: Probability and Likelihood (8 questions)
- Quiz: Sample Spaces, Events and Trees (8 questions)