Grade six, Edexcel GCSE Maths

Revision Notes

How to count combinations of things

When you have a question like “How many ways…?”

  1. SYSTEMATIC listing can help in simple cases
  2. Write down the thing you are counting with “AND”s and “OR”s
  3. Remember that (like in Probability problems):
    AND means ×
    OR means +
  4. Beware of REPETITIONS and whether they are allowed or not

(If they are not we reduce the number of options by one)

Example

Counting, IGCSE & GCSE Maths revision notes
Counting, IGCSE & GCSE Maths revision notes

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Edexcel GCSE Maths Notes

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