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Sections

Permutations and Combinations

Pick a section. You read the idea first, then answer questions on it.

1. One question decides everything1 ideaRead

2. Multiplying choices across stages2 ideasRead

3. Adding choices across alternatives2 ideasRead

4. Factorials2 ideasRead

5. Permutations: order matters, nothing repeats2 ideasRead

6. When repetition is allowed2 ideasRead

7. When the objects are not all different2 ideasRead

8. Combinations: dividing the order back out2 ideasRead

9. Two identities that follow for free2 ideasRead

10. Two questions, four formulas1 ideaRead

11. Two traps this chapter sets2 ideasRead

12. Practice set5 ideasRead

13. Chapter-end problems1 ideaRead

14. JEE-application problems1 ideaRead