# OCME · Knowledge & practice explorer

302 MKO / 1,441 families / 360 batches / 36,000 questions.

36,000 second-context math/bilingual reviewed; 0 display/symbol-checked candidates. Source questions: candidate. English: ai_candidate. No new proof, Lean, SREG or training.

1 results; page 1/1.

## Question 30907: Ordered/Unordered Counts, Factorial, and Empty Selection

- ID: `q-20261011-advance-20261015-r06-permutation-combination-0007`; number: 30907
- Processing: second_context_reviewed
- MKO: [mko-permutation-combination](/en/mko/mko-permutation-combination/)
- Family: [qf-density15-selection-order-factor-triple](/en/explore/?family=qf-density15-selection-order-factor-triple)
- Batch: [batch-20261011-advance-20261015-r06-permutation-combination-foundations](/en/explore/?batch=batch-20261011-advance-20261015-r06-permutation-combination-foundations)
- [Derivation](/en/questions/q-20261011-advance-20261015-r06-permutation-combination-0007/) / [Markdown](/en/questions/q-20261011-advance-20261015-r06-permutation-combination-0007/index.md) / [JSON](/data/question-derivations/questions/q-20261011-advance-20261015-r06-permutation-combination-0007.json)