IGCSE Maths / Probability

At least one, and the complement

Edexcel International GCSE Maths (4MA1), chapter 20: Probability, specification point 6.3b. Part of the full course.

Read the revision notes · IGCSE Maths past papers

“At least one” means one or more events happen. It is often quickest to find the probability that none happen, then subtract that from 1.

More lessons in Probability

• The language of probability and the probability scale
• Listing outcomes systematically
• Theoretical probability and sample space
• Relative frequency and mutually exclusive events
• Expected frequency and relative frequency
• Multiplying independent probabilities
• Tree diagrams with replacement
• Tree diagrams without replacement
• Three stage tree diagrams
• Probability problem solving
• Conditional probability from a two way table
• Conditional probability from a Venn diagram
• Conditional probability without replacement
• Forming an equation from a probability