GCSE MATHS REVISION
NOTES
Foundation & higher | exam focused
What You Need to Know
Probability measures how likely something is to happen.
Key Rules
Formula :
Probability = number of outcomes ÷ total outcomes
Rule 1: When you use the word AND you multiply the probabilities
Rule 2: When you use the word OR you add the probabilities.
Worked Example
A simple worked example illustrating the key concepts.
Question: What is the probability of Rolling a 6 on a die = 1/6
Solution: Number of outcomes = 1, Total outcomes = 6
Question: A dice is rolled and a card is picked from the deck of 10 cards each with a number
between 1 - 10 on them. What is the probability of rolling a 3 and getting a 10?
Solution: Dice probability = 1/6, cards probability = 1/10 → ⅙ x 1/10 = 1/60
NOTES
Foundation & higher | exam focused
What You Need to Know
Probability measures how likely something is to happen.
Key Rules
Formula :
Probability = number of outcomes ÷ total outcomes
Rule 1: When you use the word AND you multiply the probabilities
Rule 2: When you use the word OR you add the probabilities.
Worked Example
A simple worked example illustrating the key concepts.
Question: What is the probability of Rolling a 6 on a die = 1/6
Solution: Number of outcomes = 1, Total outcomes = 6
Question: A dice is rolled and a card is picked from the deck of 10 cards each with a number
between 1 - 10 on them. What is the probability of rolling a 3 and getting a 10?
Solution: Dice probability = 1/6, cards probability = 1/10 → ⅙ x 1/10 = 1/60
