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How a topic is taught

  1. Read the idea

    A short lesson states the idea plainly, with the definitions and the formulas you need and nothing you do not.

  2. Follow worked examples

    Each example is solved one step at a time, with the reason for every step beside it.

  3. Practise with new numbers

    Answer a question and it is checked at once. Ask for new numbers and the same kind of question comes back different, with its full solution.

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