General proof for combinatorics
424
Proving Pascal's Rule : ${{n} \choose {r}}={{n-1} \choose {r-1}}+{{n-1} \choose r}$ when $1\leq r\leq n$
67927
Combinatorial argument for the identity $k\binom{n}{k} = n\binom{n-1}{k-1}$
142978
combinatorics: sum of product of integer compositions
1139
Combinatorial proof of $\sum_{j=0}^{k} \binom{n}{j} = \sum_{j=0}^k \binom{n-1-j}{k-j}2^j$
24588
Proving the combinatorial identity ${n \choose k} = {n-2\choose k-2} + 2{n-2\choose k-1} + {n-2\choose k}$
74730
Combinatorial Proof of ${{n}\choose{k}} {{k}\choose{j}} = {{n}\choose{j}} {{n-j}\choose{k-j}}$
149216
Give a combinatorial proof to show the following for all integers $n \geq 2$.
1627
Cartesian product of an arbitrary number of sets
32350
Compilation of proofs for the summation of natural squares and cubes
122504
Factorisations of permutations
139826
arbitrary large finite sums of an uncountable set.
6366
Combinatorial proof of summation of $\sum\limits_{k = 0}^n {n \choose k}^2= {2n \choose n}$
10917
Give a combinatorial proof: $ n(n+1)2^{n-2} = \sum_{k=1}^{n}k^2\binom{n}{k} $
24212
proving how many permutations exist.
150281
Am I on the right track to figure out this combinatorics problem?
29828
Combinatorial proof of $\sum^{n}_{i=1}\binom{n}{i}i=n2^{n-1}$.
66019
Revisited: Binomial Theorem: An Inductive Proof