Combinations nCr
by Anonymous
List every possible selection, divide permutations by r! to strip out order, and see the symmetry of choosing r versus leaving out the rest.
#math#combination#counting#highschool#symmetry#probabilitystatistics#mathpractice#highschool_math#education
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About this app
Combinations nCr is an interactive mathematics lesson for understanding combinations through visual exploration. Adjust the total number of items n and the number selected r to see every selection, remove ordering by dividing permutations by r!, and compare choosing items with leaving items behind through the identity nCr = nC(n−r). Guided missions reinforce key ideas such as boundary values, peak counts, and symmetry.
Use cases
- High school students learning combinations and counting principles
- Teachers demonstrating nCr and permutation relationships
- Learners reviewing probability and statistics concepts
- Students exploring the symmetry between selected and unselected items
Features
- Interactive controls for changing n and r
- Visual display of all possible selections
- Explanation of dividing permutations by r! to remove order
- Symmetry exploration of nCr = nC(n−r)
- Four guided missions in each of three learning sections
- Reset and next controls with explanatory feedback