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Basic Probability
For equally likely outcomes, probability equals favourable outcomes divided by total outcomes.
How it works
For equally likely outcomes, probability equals favourable outcomes divided by total outcomes. Name the quantities before calculating, keep each transformation logically equivalent, and check the result against the original conditions.
Worked example
Three of eight counters are gold. Find P(gold).
- Count favourable outcomes: 3.
- Count all outcomes: 8.
- Form and simplify the fraction.
P(gold)=3/8.
Try it now
These questions come from the same validated skill generator used by the game.
Common mistakes
- Using a remembered formula without identifying what each symbol represents.
- Changing a value or condition during an intermediate step.
- Skipping the final substitution, estimate, or logical check.
Challenge
Design an event with probability 2/5 using ten equally likely cards.
Questions learners ask
What is the key idea in basic probability?
For equally likely outcomes, probability equals favourable outcomes divided by total outcomes.
How should I check an answer?
Substitute it into the original conditions, check units and signs, and decide whether its size is reasonable.